diff --git a/modules/id5IdSystem.js b/modules/id5IdSystem.js
index 95e40337e79..d08efdcb232 100644
--- a/modules/id5IdSystem.js
+++ b/modules/id5IdSystem.js
@@ -237,6 +237,7 @@ export const id5IdSubmodule = {
     }
     return cacheIdObj;
   },
+  primaryIds: ['id5id', 'trueLinkId'],
   eids: {
     'id5id': {
       getValue: function (data) {
diff --git a/modules/imuIdSystem.js b/modules/imuIdSystem.js
index 1242ca183ea..3e9904c526f 100644
--- a/modules/imuIdSystem.js
+++ b/modules/imuIdSystem.js
@@ -166,6 +166,7 @@ export const imuIdSubmodule = {
       }
     };
   },
+  primaryIds: ['imppid', 'imuid'],
   eids: {
     'imppid': {
       source: 'ppid.intimatemerger.com',
diff --git a/modules/liveIntentIdSystem.js b/modules/liveIntentIdSystem.js
index a9708910ca7..50a8dc2aa1d 100644
--- a/modules/liveIntentIdSystem.js
+++ b/modules/liveIntentIdSystem.js
@@ -302,6 +302,7 @@ export const liveIntentIdSubmodule = {
 
     return { callback: result };
   },
+  primaryIds: ['libp'],
   eids: {
     ...UID1_EIDS,
     ...UID2_EIDS,
diff --git a/modules/prebidServerBidAdapter/index.js b/modules/prebidServerBidAdapter/index.js
index edae21e97a7..4212ab294f5 100644
--- a/modules/prebidServerBidAdapter/index.js
+++ b/modules/prebidServerBidAdapter/index.js
@@ -4,7 +4,6 @@ import {
   deepClone,
   flatten,
   generateUUID,
-  getPrebidInternal,
   insertUserSyncIframe,
   isNumber,
   isPlainObject,
@@ -16,7 +15,7 @@ import {
   triggerPixel,
   uniques,
 } from '../../src/utils.js';
-import { EVENTS, REJECTION_REASON, S2S } from '../../src/constants.js';
+import {EVENTS, REJECTION_REASON, S2S} from '../../src/constants.js';
 import adapterManager, {s2sActivityParams} from '../../src/adapterManager.js';
 import {config} from '../../src/config.js';
 import {addPaapiConfig, isValid} from '../../src/adapters/bidderFactory.js';
@@ -37,8 +36,6 @@ const TYPE = S2S.SRC;
 let _syncCount = 0;
 let _s2sConfigs;
 
-let eidPermissions;
-
 /**
  * @typedef {Object} AdapterOptions
  * @summary s2sConfig parameter that adds arguments to resulting OpenRTB payload that goes to Prebid Server
@@ -553,7 +550,7 @@ export const processPBSRequest = hook('sync', function (s2sBidRequest, bidReques
     .reduce(flatten, [])
     .filter(uniques);
 
-  const request = s2sBidRequest.metrics.measureTime('buildRequests', () => buildPBSRequest(s2sBidRequest, bidRequests, adUnits, requestedBidders, eidPermissions));
+  const request = s2sBidRequest.metrics.measureTime('buildRequests', () => buildPBSRequest(s2sBidRequest, bidRequests, adUnits, requestedBidders));
   const requestJson = request && JSON.stringify(request);
   logInfo('BidRequest: ' + requestJson);
   const endpointUrl = getMatchingConsentUrl(s2sBidRequest.s2sConfig.endpoint, gdprConsent);
@@ -605,14 +602,4 @@ function shouldEmitNonbids(s2sConfig, response) {
   return s2sConfig?.extPrebid?.returnallbidstatus && response?.ext?.seatnonbid;
 }
 
-/**
- * Global setter that sets eids permissions for bidders
- * This setter is to be used by userId module when included
- * @param {Array} newEidPermissions
- */
-function setEidPermissions(newEidPermissions) {
-  eidPermissions = newEidPermissions;
-}
-getPrebidInternal().setEidPermissions = setEidPermissions;
-
 adapterManager.registerBidAdapter(new PrebidServer(), 'prebidServer');
diff --git a/modules/prebidServerBidAdapter/ortbConverter.js b/modules/prebidServerBidAdapter/ortbConverter.js
index 242c65c7dfa..01da91b57a7 100644
--- a/modules/prebidServerBidAdapter/ortbConverter.js
+++ b/modules/prebidServerBidAdapter/ortbConverter.js
@@ -1,17 +1,7 @@
 import {ortbConverter} from '../../libraries/ortbConverter/converter.js';
-import {
-  deepAccess,
-  deepSetValue,
-  getBidRequest,
-  getDefinedParams,
-  isArray,
-  logError,
-  logWarn,
-  mergeDeep,
-  timestamp
-} from '../../src/utils.js';
+import {deepAccess, deepSetValue, getBidRequest, logError, logWarn, mergeDeep, timestamp} from '../../src/utils.js';
 import {config} from '../../src/config.js';
-import { STATUS, S2S } from '../../src/constants.js';
+import {S2S, STATUS} from '../../src/constants.js';
 import {createBid} from '../../src/bidfactory.js';
 import {pbsExtensions} from '../../libraries/pbsExtensions/pbsExtensions.js';
 import {setImpBidParams} from '../../libraries/pbsExtensions/processors/params.js';
@@ -55,7 +45,7 @@ const PBS_CONVERTER = ortbConverter({
     if (!imps.length) {
       logError('Request to Prebid Server rejected due to invalid media type(s) in adUnit.');
     } else {
-      let {s2sBidRequest, requestedBidders, eidPermissions} = context;
+      let {s2sBidRequest} = context;
       const request = buildRequest(imps, proxyBidderRequest, context);
 
       request.tmax = s2sBidRequest.s2sConfig.timeout ?? Math.min(s2sBidRequest.requestBidsTimeout * 0.75, s2sBidRequest.s2sConfig.maxTimeout ?? s2sDefaultConfig.maxTimeout);
@@ -67,16 +57,6 @@ const PBS_CONVERTER = ortbConverter({
         }
       })
 
-      if (isArray(eidPermissions) && eidPermissions.length > 0) {
-        if (requestedBidders && isArray(requestedBidders)) {
-          eidPermissions = eidPermissions.map(p => ({
-            ...p,
-            bidders: p.bidders.filter(bidder => requestedBidders.includes(bidder))
-          }))
-        }
-        deepSetValue(request, 'ext.prebid.data.eidpermissions', eidPermissions);
-      }
-
       if (!context.transmitTids) {
         deepSetValue(request, 'ext.prebid.createtids', false);
       }
@@ -253,7 +233,7 @@ const PBS_CONVERTER = ortbConverter({
   },
 });
 
-export function buildPBSRequest(s2sBidRequest, bidderRequests, adUnits, requestedBidders, eidPermissions) {
+export function buildPBSRequest(s2sBidRequest, bidderRequests, adUnits, requestedBidders) {
   const requestTimestamp = timestamp();
   const impIds = new Set();
   const proxyBidRequests = [];
@@ -295,7 +275,6 @@ export function buildPBSRequest(s2sBidRequest, bidderRequests, adUnits, requeste
     proxyBidRequests.push({
       ...adUnit,
       adUnitCode: adUnit.code,
-      ...getDefinedParams(actualBidRequests.values().next().value || {}, ['userId', 'userIdAsEids', 'schain']),
       pbsData: {impId, actualBidRequests, adUnit},
     });
   });
@@ -317,7 +296,6 @@ export function buildPBSRequest(s2sBidRequest, bidderRequests, adUnits, requeste
       s2sBidRequest,
       requestedBidders,
       actualBidderRequests: bidderRequests,
-      eidPermissions,
       nativeRequest: s2sBidRequest.s2sConfig.ortbNative,
       getRedactor,
       transmitTids: isActivityAllowed(ACTIVITY_TRANSMIT_TID, s2sParams),
diff --git a/modules/userId/eids.js b/modules/userId/eids.js
index 930dd34b23d..bf425b8d9f0 100644
--- a/modules/userId/eids.js
+++ b/modules/userId/eids.js
@@ -1,4 +1,4 @@
-import {deepAccess, deepClone, isFn, isPlainObject, isStr} from '../../src/utils.js';
+import {deepClone, isFn, isStr} from '../../src/utils.js';
 /*
  * @typedef {import('../modules/userId/index.js').SubmoduleContainer} SubmoduleContainer
  */
@@ -6,25 +6,24 @@ import {deepAccess, deepClone, isFn, isPlainObject, isStr} from '../../src/utils
 export const EID_CONFIG = new Map();
 
 // this function will create an eid object for the given UserId sub-module
-function createEidObject(userIdData, subModuleKey) {
-  const conf = EID_CONFIG.get(subModuleKey);
-  if (conf && userIdData) {
+function createEidObject(userIdData, subModuleKey, eidConf) {
+  if (eidConf && userIdData) {
     let eid = {};
-    eid.source = isFn(conf['getSource']) ? conf['getSource'](userIdData) : conf['source'];
-    const value = isFn(conf['getValue']) ? conf['getValue'](userIdData) : userIdData;
+    eid.source = isFn(eidConf['getSource']) ? eidConf['getSource'](userIdData) : eidConf['source'];
+    const value = isFn(eidConf['getValue']) ? eidConf['getValue'](userIdData) : userIdData;
     if (isStr(value)) {
-      const uid = { id: value, atype: conf['atype'] };
+      const uid = { id: value, atype: eidConf['atype'] };
       // getUidExt
-      if (isFn(conf['getUidExt'])) {
-        const uidExt = conf['getUidExt'](userIdData);
+      if (isFn(eidConf['getUidExt'])) {
+        const uidExt = eidConf['getUidExt'](userIdData);
         if (uidExt) {
           uid.ext = uidExt;
         }
       }
       eid.uids = [uid];
       // getEidExt
-      if (isFn(conf['getEidExt'])) {
-        const eidExt = conf['getEidExt'](userIdData);
+      if (isFn(eidConf['getEidExt'])) {
+        const eidExt = eidConf['getEidExt'](userIdData);
         if (eidExt) {
           eid.ext = eidExt;
         }
@@ -35,7 +34,7 @@ function createEidObject(userIdData, subModuleKey) {
   return null;
 }
 
-export function createEidsArray(bidRequestUserId) {
+export function createEidsArray(bidRequestUserId, eidConfigs = EID_CONFIG) {
   const allEids = {};
   function collect(eid) {
     const key = JSON.stringify([eid.source?.toLowerCase(), eid.ext]);
@@ -48,31 +47,24 @@ export function createEidsArray(bidRequestUserId) {
 
   Object.entries(bidRequestUserId).forEach(([name, values]) => {
     values = Array.isArray(values) ? values : [values];
-    const eids = name === 'pubProvidedId' ? deepClone(values) : values.map(value => createEidObject(value, name));
+    const eids = name === 'pubProvidedId' ? deepClone(values) : values.map(value => createEidObject(value, name, eidConfigs.get(name)));
     eids.filter(eid => eid != null).forEach(collect);
   })
   return Object.values(allEids);
 }
 
 /**
- * @param {SubmoduleContainer[]} submodules
+ * @param {SubmodulePriorityMap} priorityMap
  */
-export function buildEidPermissions(submodules) {
-  let eidPermissions = [];
-  submodules.filter(i => isPlainObject(i.idObj) && Object.keys(i.idObj).length)
-    .forEach(i => {
-      Object.keys(i.idObj).forEach(key => {
-        const eidConf = EID_CONFIG.get(key) || {};
-        if (deepAccess(i, 'config.bidders') && Array.isArray(i.config.bidders) &&
-          eidConf.source) {
-          eidPermissions.push(
-            {
-              source: eidConf.source,
-              bidders: i.config.bidders
-            }
-          );
-        }
-      });
-    });
-  return eidPermissions;
+export function getEids(priorityMap) {
+  const eidConfigs = new Map();
+  const idValues = {};
+  Object.entries(priorityMap).forEach(([key, submodules]) => {
+    const submodule = submodules.find(mod => mod.idObj?.[key] != null);
+    if (submodule) {
+      idValues[key] = submodule.idObj[key];
+      eidConfigs.set(key, submodule.submodule.eids?.[key])
+    }
+  })
+  return createEidsArray(idValues, eidConfigs);
 }
diff --git a/modules/userId/index.js b/modules/userId/index.js
index 31083fd1e47..f7c6e1c5433 100644
--- a/modules/userId/index.js
+++ b/modules/userId/index.js
@@ -126,14 +126,18 @@
  * @property {(function|undefined)} callback - function that will return an id
  */
 
-import {find, includes} from '../../src/polyfill.js';
+/**
+ * @typedef {{[idKey: string]: SubmoduleContainer[]}} SubmodulePriorityMap
+ */
+
+import {find} from '../../src/polyfill.js';
 import {config} from '../../src/config.js';
 import * as events from '../../src/events.js';
 import {getGlobal} from '../../src/prebidGlobal.js';
 import adapterManager, {gdprDataHandler} from '../../src/adapterManager.js';
 import {EVENTS} from '../../src/constants.js';
 import {module, ready as hooksReady} from '../../src/hook.js';
-import {buildEidPermissions, createEidsArray, EID_CONFIG} from './eids.js';
+import {EID_CONFIG, getEids} from './eids.js';
 import {
   getCoreStorageManager,
   getStorageManager,
@@ -144,7 +148,6 @@ import {
   deepAccess,
   deepSetValue,
   delayExecution,
-  getPrebidInternal,
   isArray,
   isEmpty,
   isFn,
@@ -157,7 +160,6 @@ import {
 } from '../../src/utils.js';
 import {getPPID as coreGetPPID} from '../../src/adserver.js';
 import {defer, GreedyPromise} from '../../src/utils/promise.js';
-import {registerOrtbProcessor, REQUEST} from '../../src/pbjsORTB.js';
 import {newMetrics, timedAuctionHook, useMetrics} from '../../src/utils/perfMetrics.js';
 import {findRootDomain} from '../../src/fpd/rootDomain.js';
 import {allConsent, GDPR_GVLIDS} from '../../src/consentHandler.js';
@@ -166,6 +168,7 @@ import {isActivityAllowed} from '../../src/activities/rules.js';
 import {ACTIVITY_ENRICH_EIDS} from '../../src/activities/activities.js';
 import {activityParams} from '../../src/activities/activityParams.js';
 import {USERSYNC_DEFAULT_CONFIG} from '../../src/userSync.js';
+import {startAuction} from '../../src/prebid.js';
 
 const MODULE_NAME = 'User ID';
 const COOKIE = STORAGE_TYPE_COOKIES;
@@ -182,7 +185,7 @@ let addedUserIdHook = false;
 /** @type {SubmoduleContainer[]} */
 let submodules = [];
 
-/** @type {SubmoduleContainer[]} */
+/** @type {PriorityMaps} */
 let initializedSubmodules;
 
 /** @type {SubmoduleConfig[]} */
@@ -327,13 +330,6 @@ export function deleteStoredValue(submodule) {
   });
 }
 
-function setPrebidServerEidPermissions(initializedSubmodules) {
-  let setEidPermissions = getPrebidInternal().setEidPermissions;
-  if (typeof setEidPermissions === 'function' && isArray(initializedSubmodules)) {
-    setEidPermissions(buildEidPermissions(initializedSubmodules));
-  }
-}
-
 function getValueFromCookie(submodule, storedKey) {
   return submodule.storageMgr.getCookie(storedKey)
 }
@@ -387,8 +383,9 @@ function getStoredValue(submodule, key = undefined) {
 /**
  * @param {SubmoduleContainer[]} submodules
  * @param {function} cb - callback for after processing is done.
+ * @param {PriorityMaps} priorityMaps
  */
-function processSubmoduleCallbacks(submodules, cb, allModules) {
+function processSubmoduleCallbacks(submodules, cb, priorityMaps) {
   cb = uidMetrics().fork().startTiming('userId.callbacks.total').stopBefore(cb);
   const done = delayExecution(() => {
     clearTimeout(timeoutID);
@@ -404,7 +401,8 @@ function processSubmoduleCallbacks(submodules, cb, allModules) {
         }
         // cache decoded value (this is copied to every adUnit bid)
         submodule.idObj = submodule.submodule.decode(idObj, submodule.config);
-        updatePPID(getCombinedSubmoduleIds(allModules));
+        priorityMaps.refresh();
+        updatePPID(priorityMaps);
       } else {
         logInfo(`${MODULE_NAME}: ${submodule.submodule.name} - request id responded with an empty value`);
       }
@@ -422,95 +420,156 @@ function processSubmoduleCallbacks(submodules, cb, allModules) {
 }
 
 /**
- * This function will create a combined object for all subModule Ids
- * @param {SubmoduleContainer[]} submodules
+ * @param {SubmodulePriorityMap} priorityMap
+ * @returns {{}}
  */
-function getCombinedSubmoduleIds(submodules) {
-  if (!Array.isArray(submodules) || !submodules.length) {
-    return {};
-  }
-  return getPrioritizedCombinedSubmoduleIds(submodules)
+function getIds(priorityMap) {
+  return Object.fromEntries(
+    Object.entries(priorityMap)
+      .map(([key, submodules]) => [key, submodules.find(mod => mod.idObj?.[key] != null)?.idObj?.[key]])
+      .filter(([_, value]) => value != null)
+  )
 }
 
-/**
- * This function will return a submodule ID object for particular source name
- * @param {SubmoduleContainer[]} submodules
- * @param {string} sourceName
- */
-function getSubmoduleId(submodules, sourceName) {
-  if (!Array.isArray(submodules) || !submodules.length) {
-    return {};
+function getPrimaryIds(submodule) {
+  if (submodule.primaryIds) return submodule.primaryIds;
+  const ids = Object.keys(submodule.eids ?? {});
+  if (ids.length > 1) {
+    throw new Error(`ID submodule ${submodule.name} can provide multiple IDs, but does not specify 'primaryIds'`)
   }
-
-  const prioritisedIds = getPrioritizedCombinedSubmoduleIds(submodules);
-  const eligibleIdName = Object.keys(prioritisedIds).find(idName => {
-    const config = EID_CONFIG.get(idName);
-    return config?.source === sourceName || (isFn(config?.getSource) && config.getSource() === sourceName);
-  });
-
-  return eligibleIdName ? {[eligibleIdName]: prioritisedIds[eligibleIdName]} : [];
+  return ids;
 }
 
 /**
- * This function will create a combined object for bidder with allowed subModule Ids
- * @param {SubmoduleContainer[]} submodules
- * @param {string} bidder
+ * Given a collection of items, where each item maps to any number of IDs (getKeys) and an ID module (getIdMod),
+ * return a map from ID key to all items that map to that ID key, in order of priority (highest priority first).
+ *
+ * @template T
+ * @param {T[]} items
+ * @param {(item: T) => string[]} getKeys
+ * @param {(item: T) => Submodule} getIdMod
+ * @returns {{[key: string]: T[]}}
  */
-function getCombinedSubmoduleIdsForBidder(submodules, bidder) {
-  if (!Array.isArray(submodules) || !submodules.length || !bidder) {
-    return {};
-  }
-  const eligibleSubmodules = submodules
-    .filter(i => !i.config.bidders || !isArray(i.config.bidders) || includes(i.config.bidders, bidder))
-
-  return getPrioritizedCombinedSubmoduleIds(eligibleSubmodules);
-}
-
-function collectByPriority(submodules, getIds, getName) {
-  return Object.fromEntries(Object.entries(submodules.reduce((carry, submod) => {
-    const ids = getIds(submod);
-    ids && Object.keys(ids).forEach(key => {
-      const maybeCurrentIdPriority = idPriority[key]?.indexOf(getName(submod));
-      const currentIdPriority = isNumber(maybeCurrentIdPriority) ? maybeCurrentIdPriority : -1;
-      const currentIdState = {priority: currentIdPriority, value: ids[key]};
-      if (carry[key]) {
-        const winnerIdState = currentIdState.priority > carry[key].priority ? currentIdState : carry[key];
-        carry[key] = winnerIdState;
-      } else {
-        carry[key] = currentIdState;
-      }
-    });
-    return carry;
-  }, {})).map(([k, v]) => [k, v.value]));
+function orderByPriority(items, getKeys, getIdMod) {
+  const tally = {};
+  items.forEach(item => {
+    const module = getIdMod(item);
+    const primaryIds = getPrimaryIds(module);
+    getKeys(item).forEach(key => {
+      const keyItems = tally[key] = tally[key] ?? []
+      const keyPriority = idPriority[key]?.indexOf(module.name) ?? (primaryIds.includes(key) ? 0 : -1);
+      const pos = keyItems.findIndex(([priority]) => priority < keyPriority);
+      keyItems.splice(pos === -1 ? keyItems.length : pos, 0, [keyPriority, item])
+    })
+  })
+  return Object.fromEntries(Object.entries(tally).map(([key, items]) => [key, items.map(([_, item]) => item)]))
 }
 
 /**
- * @param {SubmoduleContainer[]} submodules
+ * @typedef {Object} PriorityMaps
+ * @property {SubmoduleContainer[]} submodules all active submodules
+ * @property {SubmodulePriorityMap} global priority map for global (not bidder-specific) submodules
+ * @property {SubmodulePriorityMap} combined priority map for ALL submodules, disregarding bidder filters
+ * @property {{[bidder: string]: SubmodulePriorityMap}} bidder priority maps for each bidder's specific submodules
+ * @property {(submodules: SubmoduleContainer[]) => void} refresh refresh priority maps, optionally adding or updating some submodules.
+ *    Should be called every time a submodule's ID is updated.
  */
-function getPrioritizedCombinedSubmoduleIds(submodules) {
-  return collectByPriority(
-    submodules.filter(i => isPlainObject(i.idObj) && Object.keys(i.idObj).length),
-    (submod) => submod.idObj,
-    (submod) => submod.submodule.name
-  )
-}
 
 /**
- * @param {AdUnit[]} adUnits
- * @param {SubmoduleContainer[]} submodules
+ * @returns PriorityMaps
  */
-function addIdDataToAdUnitBids(adUnits, submodules) {
+function mkPriorityMaps() {
+  const map = {
+    submodules: [],
+    global: {},
+    bidder: {},
+    combined: {},
+    /**
+     * @param {SubmoduleContainer[]} addtlModules
+     */
+    refresh(addtlModules = []) {
+      const refreshing = new Set(addtlModules.map(mod => mod.submodule));
+      map.submodules = map.submodules.filter((mod) => !refreshing.has(mod.submodule)).concat(addtlModules);
+      update();
+    }
+  }
+  function update() {
+    const modulesById = orderByPriority(
+      map.submodules,
+      (submod) => Object.keys(submod.idObj ?? {}),
+      (submod) => submod.submodule,
+    )
+    const global = {};
+    const bidder = {};
+    Object.entries(modulesById)
+      .forEach(([key, modules]) => {
+        let allNonGlobal = true;
+        const bidderFilters = new Set();
+        modules.map(mod => mod.config.bidders)
+          .forEach(bidders => {
+            if (Array.isArray(bidders) && bidders.length > 0) {
+              bidders.forEach(bidder => bidderFilters.add(bidder));
+            } else {
+              allNonGlobal = false;
+            }
+          })
+        if (bidderFilters.size > 0 && !allNonGlobal) {
+          logWarn(`userID modules ${modules.map(mod => mod.submodule.name).join(', ')} provide the same ID ('${key}'), but are configured for different bidders. ID will be skipped.`)
+        } else {
+          if (bidderFilters.size === 0) {
+            global[key] = modules;
+          } else {
+            bidderFilters.forEach(bidderCode => {
+              bidder[bidderCode] = bidder[bidderCode] ?? {};
+              bidder[bidderCode][key] = modules;
+            })
+          }
+        }
+      });
+    const combined = Object.values(bidder).concat([global]).reduce((combo, map) => Object.assign(combo, map), {});
+    Object.assign(map, {global, bidder, combined});
+  }
+  return map;
+}
+
+export function enrichEids(ortb2Fragments) {
+  const {global: globalFpd, bidder: bidderFpd} = ortb2Fragments;
+  const {global: globalMods, bidder: bidderMods} = initializedSubmodules;
+  const globalEids = getEids(globalMods);
+  if (globalEids.length > 0) {
+    deepSetValue(globalFpd, 'user.ext.eids', (globalFpd.user?.ext?.eids ?? []).concat(globalEids));
+  }
+  Object.entries(bidderMods).forEach(([bidder, moduleMap]) => {
+    const bidderEids = getEids(moduleMap);
+    if (bidderEids.length > 0) {
+      deepSetValue(
+        bidderFpd,
+        `${bidder}.user.ext.eids`,
+        (bidderFpd[bidder]?.user?.ext?.eids ?? []).concat(bidderEids)
+      );
+    }
+  })
+  return ortb2Fragments;
+}
+
+function addIdData({adUnits, ortb2Fragments}) {
+  ortb2Fragments = ortb2Fragments ?? {global: {}, bidder: {}}
+  enrichEids(ortb2Fragments);
   if ([adUnits].some(i => !Array.isArray(i) || !i.length)) {
     return;
   }
+  const globalIds = getIds(initializedSubmodules.global);
+  const globalEids = ortb2Fragments.global.user?.ext?.eids || [];
   adUnits.forEach(adUnit => {
     if (adUnit.bids && isArray(adUnit.bids)) {
       adUnit.bids.forEach(bid => {
-        const combinedSubmoduleIds = getCombinedSubmoduleIdsForBidder(submodules, bid.bidder);
-        if (Object.keys(combinedSubmoduleIds).length) {
-          // create a User ID object on the bid,
-          bid.userId = combinedSubmoduleIds;
-          bid.userIdAsEids = createEidsArray(combinedSubmoduleIds);
+        const bidderIds = Object.assign({}, globalIds, getIds(initializedSubmodules.bidder[bid.bidder] ?? {}));
+        const bidderEids = globalEids.concat(ortb2Fragments.bidder[bid.bidder]?.user?.ext?.eids || []);
+        if (Object.keys(bidderIds).length > 0) {
+          bid.userId = bidderIds;
+        }
+        if (bidderEids.length > 0) {
+          bid.userIdAsEids = bidderEids;
         }
       });
     }
@@ -563,7 +622,7 @@ function idSystemInitializer({delay = GreedyPromise.timeout} = {}) {
       }))
       .then(() => startCallbacks.promise.finally(initMetrics.startTiming('userId.callbacks.pending')))
       .then(checkRefs(() => {
-        const modWithCb = initModules.filter(item => isFn(item.callback));
+        const modWithCb = initModules.submodules.filter(item => isFn(item.callback));
         if (modWithCb.length) {
           return new GreedyPromise((resolve) => processSubmoduleCallbacks(modWithCb, resolve, initModules));
         }
@@ -636,13 +695,12 @@ function getPPID(eids = getUserIdsAsEids() || []) {
  * @param {Object} reqBidsConfigObj required; This is the same param that's used in pbjs.requestBids.
  * @param {function} fn required; The next function in the chain, used by hook.js
  */
-export const requestBidsHook = timedAuctionHook('userId', function requestBidsHook(fn, reqBidsConfigObj, {delay = GreedyPromise.timeout, getIds = getUserIdsAsync} = {}) {
+export const startAuctionHook = timedAuctionHook('userId', function requestBidsHook(fn, reqBidsConfigObj, {delay = GreedyPromise.timeout, getIds = getUserIdsAsync} = {}) {
   GreedyPromise.race([
     getIds().catch(() => null),
     delay(auctionDelay)
   ]).then(() => {
-    // pass available user id data to bid adapters
-    addIdDataToAdUnitBids(reqBidsConfigObj.adUnits || getGlobal().adUnits, initializedSubmodules);
+    addIdData(reqBidsConfigObj);
     uidMetrics().join(useMetrics(reqBidsConfigObj.metrics), {propagate: false, includeGroups: true});
     // calling fn allows prebid to continue processing
     fn.call(this, reqBidsConfigObj);
@@ -654,7 +712,7 @@ export const requestBidsHook = timedAuctionHook('userId', function requestBidsHo
  * Simple use case will be passing these UserIds to A9 wrapper solution
  */
 function getUserIds() {
-  return getCombinedSubmoduleIds(initializedSubmodules)
+  return getIds(initializedSubmodules.combined)
 }
 
 /**
@@ -662,7 +720,7 @@ function getUserIds() {
  * Simple use case will be passing these UserIds to A9 wrapper solution
  */
 function getUserIdsAsEids() {
-  return createEidsArray(getUserIds())
+  return getEids(initializedSubmodules.combined)
 }
 
 /**
@@ -671,7 +729,7 @@ function getUserIdsAsEids() {
  */
 
 function getUserIdsAsEidBySource(sourceName) {
-  return createEidsArray(getSubmoduleId(initializedSubmodules, sourceName))[0];
+  return getUserIdsAsEids().filter(eid => eid.source === sourceName)[0];
 }
 
 /**
@@ -802,7 +860,7 @@ function consentChanged(submodule) {
   return !storedConsent || storedConsent !== getConsentHash();
 }
 
-function populateSubmoduleId(submodule, forceRefresh, allSubmodules) {
+function populateSubmoduleId(submodule, forceRefresh) {
   // TODO: the ID submodule API only takes GDPR consent; it should be updated now that GDPR
   // is only a tiny fraction of a vast consent universe
   const gdprConsent = gdprDataHandler.getConsentData();
@@ -857,12 +915,12 @@ function populateSubmoduleId(submodule, forceRefresh, allSubmodules) {
       if (response.id) { submodule.idObj = submodule.submodule.decode(response.id, submodule.config); }
     }
   }
-  updatePPID(getCombinedSubmoduleIds(allSubmodules));
 }
 
-function updatePPID(userIds = getUserIds()) {
-  if (userIds && ppidSource) {
-    const ppid = getPPID(createEidsArray(userIds));
+function updatePPID(priorityMaps) {
+  const eids = getEids(priorityMaps.combined);
+  if (eids.length && ppidSource) {
+    const ppid = getPPID(eids);
     if (ppid) {
       if (isGptPubadsDefined()) {
         window.googletag.pubads().setPublisherProvidedId(ppid);
@@ -877,7 +935,7 @@ function updatePPID(userIds = getUserIds()) {
   }
 }
 
-function initSubmodules(dest, submodules, forceRefresh = false) {
+function initSubmodules(priorityMaps, submodules, forceRefresh = false) {
   return uidMetrics().fork().measureTime('userId.init.modules', function () {
     if (!submodules.length) return []; // to simplify log messages from here on
 
@@ -902,7 +960,7 @@ function initSubmodules(dest, submodules, forceRefresh = false) {
     const initialized = submodules.reduce((carry, submodule) => {
       return submoduleMetrics(submodule.submodule.name).measureTime('init', () => {
         try {
-          populateSubmoduleId(submodule, forceRefresh, submodules);
+          populateSubmoduleId(submodule, forceRefresh);
           carry.push(submodule);
         } catch (e) {
           logError(`Error in userID module '${submodule.submodule.name}':`, e);
@@ -910,29 +968,12 @@ function initSubmodules(dest, submodules, forceRefresh = false) {
         return carry;
       })
     }, []);
-    if (initialized.length) {
-      setPrebidServerEidPermissions(initialized);
-    }
-    initialized.forEach(updateInitializedSubmodules.bind(null, dest));
+    priorityMaps.refresh(initialized);
+    updatePPID(priorityMaps);
     return initialized;
   })
 }
 
-function updateInitializedSubmodules(dest, submodule) {
-  let updated = false;
-  for (let i = 0; i < dest.length; i++) {
-    if (submodule.config.name.toLowerCase() === dest[i].config.name.toLowerCase()) {
-      updated = true;
-      dest[i] = submodule;
-      break;
-    }
-  }
-
-  if (!updated) {
-    dest.push(submodule);
-  }
-}
-
 function getConfiguredStorageTypes(config) {
   return config?.storage?.type?.trim().split(/\s*&\s*/) || [];
 }
@@ -1039,11 +1080,13 @@ function canUseStorage(submodule) {
 
 function updateEIDConfig(submodules) {
   EID_CONFIG.clear();
-  Object.entries(collectByPriority(
-    submodules,
-    (mod) => mod.eids,
-    (mod) => mod.name
-  )).forEach(([id, conf]) => EID_CONFIG.set(id, conf));
+  Object.entries(
+    orderByPriority(
+      submodules,
+      (mod) => Object.keys(mod.eids || {}),
+      (mod) => mod
+    )
+  ).forEach(([key, submodules]) => EID_CONFIG.set(key, submodules[0].eids[key]))
 }
 
 /**
@@ -1076,25 +1119,26 @@ function updateSubmodules() {
   }).filter(submodule => submodule !== null)
     .forEach((sm) => submodules.push(sm));
 
-  if (!addedUserIdHook && submodules.length) {
-    // priority value 40 will load after consentManagement with a priority of 50
-    getGlobal().requestBids.before(requestBidsHook, 40);
-    adapterManager.callDataDeletionRequest.before(requestDataDeletion);
-    coreGetPPID.after((next) => next(getPPID()));
+  if (submodules.length) {
+    if (!addedUserIdHook) {
+      startAuction.before(startAuctionHook, 100) // use higher priority than dataController / rtd
+      adapterManager.callDataDeletionRequest.before(requestDataDeletion);
+      coreGetPPID.after((next) => next(getPPID()));
+      addedUserIdHook = true;
+    }
     logInfo(`${MODULE_NAME} - usersync config updated for ${submodules.length} submodules: `, submodules.map(a => a.submodule.name));
-    addedUserIdHook = true;
   }
 }
 
 /**
  * This function will update the idPriority according to the provided configuration
  * @param {Object} idPriorityConfig
- * @param {SubmoduleContainer[]} submodules
+ * @param {Submodule[]} submodules
  */
 function updateIdPriority(idPriorityConfig, submodules) {
   if (idPriorityConfig) {
     const result = {};
-    const aliasToName = new Map(submodules.map(s => s.submodule.aliasName ? [s.submodule.aliasName, s.submodule.name] : []));
+    const aliasToName = new Map(submodules.map(s => s.aliasName ? [s.aliasName, s.name] : []));
     Object.keys(idPriorityConfig).forEach(key => {
       const priority = isArray(idPriorityConfig[key]) ? [...idPriorityConfig[key]].reverse() : []
       result[key] = priority.map(s => aliasToName.has(s) ? aliasToName.get(s) : s);
@@ -1103,6 +1147,8 @@ function updateIdPriority(idPriorityConfig, submodules) {
   } else {
     idPriority = {};
   }
+  initializedSubmodules.refresh();
+  updateEIDConfig(submodules)
 }
 
 export function requestDataDeletion(next, ...args) {
@@ -1153,8 +1199,7 @@ export function init(config, {delay = GreedyPromise.timeout} = {}) {
   ppidSource = undefined;
   submodules = [];
   configRegistry = [];
-  addedUserIdHook = false;
-  initializedSubmodules = [];
+  initializedSubmodules = mkPriorityMaps();
   initIdSystem = idSystemInitializer({delay});
   if (configListener != null) {
     configListener();
@@ -1172,7 +1217,7 @@ export function init(config, {delay = GreedyPromise.timeout} = {}) {
         syncDelay = isNumber(userSync.syncDelay) ? userSync.syncDelay : USERSYNC_DEFAULT_CONFIG.syncDelay
         auctionDelay = isNumber(userSync.auctionDelay) ? userSync.auctionDelay : USERSYNC_DEFAULT_CONFIG.auctionDelay;
         updateSubmodules();
-        updateIdPriority(userSync.idPriority, submodules);
+        updateIdPriority(userSync.idPriority, submoduleRegistry);
         initIdSystem({ready: true});
       }
     }
@@ -1192,11 +1237,3 @@ export function init(config, {delay = GreedyPromise.timeout} = {}) {
 init(config);
 
 module('userId', attachIdSystem, { postInstallAllowed: true });
-
-export function setOrtbUserExtEids(ortbRequest, bidderRequest, context) {
-  const eids = deepAccess(context, 'bidRequests.0.userIdAsEids');
-  if (eids && Object.keys(eids).length > 0) {
-    deepSetValue(ortbRequest, 'user.ext.eids', eids.concat(ortbRequest.user?.ext?.eids || []));
-  }
-}
-registerOrtbProcessor({type: REQUEST, name: 'userExtEids', fn: setOrtbUserExtEids});
diff --git a/test/spec/modules/conversantBidAdapter_spec.js b/test/spec/modules/conversantBidAdapter_spec.js
index d68383b9118..2b2d44b3b06 100644
--- a/test/spec/modules/conversantBidAdapter_spec.js
+++ b/test/spec/modules/conversantBidAdapter_spec.js
@@ -560,16 +560,10 @@ describe('Conversant adapter tests', function() {
       // clone bidRequests
       let requests = utils.deepClone(bidRequests);
 
-      const uid = {pubcid: '112233', idl_env: '334455'};
       const eidArray = [{'source': 'pubcid.org', 'uids': [{'id': '112233', 'atype': 1}]}, {'source': 'liveramp.com', 'uids': [{'id': '334455', 'atype': 3}]}];
 
-      // add pubcid to every entry
-      requests.forEach((unit) => {
-        Object.assign(unit, {userId: uid});
-        Object.assign(unit, {userIdAsEids: eidArray});
-      });
       //  construct http post payload
-      const payload = spec.buildRequests(requests, {}).data;
+      const payload = spec.buildRequests(requests, {ortb2: {user: {ext: {eids: eidArray}}}}).data;
       expect(payload).to.have.deep.nested.property('user.ext.eids', [
         {source: 'pubcid.org', uids: [{id: '112233', atype: 1}]},
         {source: 'liveramp.com', uids: [{id: '334455', atype: 3}]}
diff --git a/test/spec/modules/criteoBidAdapter_spec.js b/test/spec/modules/criteoBidAdapter_spec.js
index 079357ab4fe..00f05a2dc4d 100755
--- a/test/spec/modules/criteoBidAdapter_spec.js
+++ b/test/spec/modules/criteoBidAdapter_spec.js
@@ -758,19 +758,28 @@ describe('The Criteo bidding adapter', function () {
               sizes: [[728, 90]]
             }
           },
-          userIdAsEids: [
-            {
-              source: 'criteo.com',
-              uids: [{
-                id: 'abc',
-                atype: 1
-              }]
-            }
-          ],
           params: {}
         },
       ];
-      const request = spec.buildRequests(bidRequests, syncAddFPDToBidderRequest(bidderRequest));
+      const br = {
+        ...bidderRequest,
+        ortb2: {
+          user: {
+            ext: {
+              eids: [
+                {
+                  source: 'criteo.com',
+                  uids: [{
+                    id: 'abc',
+                    atype: 1
+                  }]
+                }
+              ]
+            }
+          }
+        }
+      }
+      const request = spec.buildRequests(bidRequests, syncAddFPDToBidderRequest(br));
       const ortbRequest = request.data;
       expect(ortbRequest.user.ext.eids).to.deep.equal([
         {
diff --git a/test/spec/modules/id5IdSystem_spec.js b/test/spec/modules/id5IdSystem_spec.js
index 2703c6681e7..456bd92cb02 100644
--- a/test/spec/modules/id5IdSystem_spec.js
+++ b/test/spec/modules/id5IdSystem_spec.js
@@ -4,7 +4,7 @@ import {
   coreStorage,
   getConsentHash,
   init,
-  requestBidsHook,
+  startAuctionHook,
   setSubmoduleRegistry
 } from '../../../modules/userId/index.js';
 import {config} from '../../../src/config.js';
@@ -912,7 +912,7 @@ describe('ID5 ID System', function () {
       setSubmoduleRegistry([id5System.id5IdSubmodule]);
       config.setConfig(getFetchLocalStorageConfig());
 
-      requestBidsHook(wrapAsyncExpects(done, () => {
+      startAuctionHook(wrapAsyncExpects(done, () => {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property(`userId.${ID5_EIDS_NAME}`);
@@ -940,7 +940,7 @@ describe('ID5 ID System', function () {
       setSubmoduleRegistry([id5System.id5IdSubmodule]);
       config.setConfig(getFetchLocalStorageConfig());
 
-      requestBidsHook(function () {
+      startAuctionHook(function () {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property(`userId.euid`);
@@ -969,7 +969,7 @@ describe('ID5 ID System', function () {
       setSubmoduleRegistry([id5System.id5IdSubmodule]);
       config.setConfig(getFetchLocalStorageConfig());
 
-      requestBidsHook(wrapAsyncExpects(done, function () {
+      startAuctionHook(wrapAsyncExpects(done, function () {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property(`userId.trueLinkId`);
@@ -992,7 +992,7 @@ describe('ID5 ID System', function () {
       setSubmoduleRegistry([id5System.id5IdSubmodule]);
       config.setConfig(getValueConfig(ID5_STORED_ID));
 
-      requestBidsHook(function () {
+      startAuctionHook(function () {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property(`userId.${ID5_EIDS_NAME}`);
@@ -1022,7 +1022,7 @@ describe('ID5 ID System', function () {
       setSubmoduleRegistry([id5System.id5IdSubmodule]);
       config.setConfig(id5Config);
       return new Promise((resolve) => {
-        requestBidsHook(() => {
+        startAuctionHook(() => {
           resolve();
         }, {adUnits});
       }).then(() => {
diff --git a/test/spec/modules/idxIdSystem_spec.js b/test/spec/modules/idxIdSystem_spec.js
index 0d30808cc1f..bfe9d1b1e68 100644
--- a/test/spec/modules/idxIdSystem_spec.js
+++ b/test/spec/modules/idxIdSystem_spec.js
@@ -1,7 +1,7 @@
 import { expect } from 'chai';
 import {find} from 'src/polyfill.js';
 import { config } from 'src/config.js';
-import { init, requestBidsHook, setSubmoduleRegistry } from 'modules/userId/index.js';
+import { init, startAuctionHook, setSubmoduleRegistry } from 'modules/userId/index.js';
 import { storage, idxIdSubmodule } from 'modules/idxIdSystem.js';
 import {mockGdprConsent} from '../../helpers/consentData.js';
 import 'src/prebid.js';
@@ -101,10 +101,15 @@ describe('IDx ID System', () => {
 
     afterEach(() => {
       sandbox.restore();
+      config.resetConfig();
+    })
+
+    after(() => {
+      init(config);
     })
 
     it('when a stored IDx exists it is added to bids', (done) => {
-      requestBidsHook(() => {
+      startAuctionHook(() => {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property('userId.idx');
diff --git a/test/spec/modules/improvedigitalBidAdapter_spec.js b/test/spec/modules/improvedigitalBidAdapter_spec.js
index 215e0b8ac98..5dc94f544ea 100644
--- a/test/spec/modules/improvedigitalBidAdapter_spec.js
+++ b/test/spec/modules/improvedigitalBidAdapter_spec.js
@@ -535,7 +535,7 @@ describe('Improve Digital Adapter Tests', function () {
     });
 
     it('should add eids', function () {
-      const userIdAsEids = [
+      const eids = [
         {
           source: 'id5-sync.com',
           uids: [{
@@ -551,9 +551,10 @@ describe('Improve Digital Adapter Tests', function () {
           id: '1111'
         }]
       }]}};
-      const bidRequest = Object.assign({}, simpleBidRequest);
-      bidRequest.userIdAsEids = userIdAsEids;
-      const request = spec.buildRequests([bidRequest], bidderRequestReferrer)[0];
+      const request = spec.buildRequests([simpleBidRequest], {
+        ...bidderRequestReferrer,
+        ortb2: {user: {ext: {eids: eids}}}
+      })[0];
       const payload = JSON.parse(request.data);
       expect(payload.user).to.deep.equal(expectedUserObject);
     });
diff --git a/test/spec/modules/lmpIdSystem_spec.js b/test/spec/modules/lmpIdSystem_spec.js
index c17df3a7ef3..28f8ba0697d 100644
--- a/test/spec/modules/lmpIdSystem_spec.js
+++ b/test/spec/modules/lmpIdSystem_spec.js
@@ -1,7 +1,7 @@
 import { expect } from 'chai';
 import { find } from 'src/polyfill.js';
 import { config } from 'src/config.js';
-import { init, requestBidsHook, setSubmoduleRegistry } from 'modules/userId/index.js';
+import { init, startAuctionHook, setSubmoduleRegistry } from 'modules/userId/index.js';
 import { storage, lmpIdSubmodule } from 'modules/lmpIdSystem.js';
 import { mockGdprConsent } from '../../helpers/consentData.js';
 import 'src/prebid.js';
@@ -100,10 +100,15 @@ describe('LMPID System', () => {
 
     afterEach(() => {
       sandbox.restore();
+      config.resetConfig();
     });
 
+    after(() => {
+      init(config);
+    })
+
     it('when a stored LMPID exists it is added to bids', (done) => {
-      requestBidsHook(() => {
+      startAuctionHook(() => {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property('userId.lmpid');
diff --git a/test/spec/modules/openxBidAdapter_spec.js b/test/spec/modules/openxBidAdapter_spec.js
index dbc036c860b..faaab727b17 100644
--- a/test/spec/modules/openxBidAdapter_spec.js
+++ b/test/spec/modules/openxBidAdapter_spec.js
@@ -972,7 +972,7 @@ describe('OpenxRtbAdapter', function () {
       });
 
       context('when there are userid providers', function () {
-        const userIdAsEids = [
+        const eids = [
           {
             source: 'adserver.org',
             uids: [{
@@ -1003,14 +1003,12 @@ describe('OpenxRtbAdapter', function () {
         ];
 
         it(`should send the user id under the extended ids`, function () {
-          const bidRequestsWithUserId = [{
+          const bidRequests = [{
             bidder: 'openx',
             params: {
               unit: '11',
               delDomain: 'test-del-domain'
             },
-            userId: {
-            },
             adUnitCode: 'adunit-code',
             mediaTypes: {
               banner: {
@@ -1020,12 +1018,12 @@ describe('OpenxRtbAdapter', function () {
             bidId: 'test-bid-id-1',
             bidderRequestId: 'test-bid-request-1',
             auctionId: 'test-auction-1',
-            userIdAsEids: userIdAsEids
           }];
           // enrich bid request with userId key/value
 
-          const request = spec.buildRequests(bidRequestsWithUserId, mockBidderRequest);
-          expect(request[0].data.user.ext.eids).to.eql(userIdAsEids);
+          mockBidderRequest.ortb2 = {user: {ext: {eids}}}
+          const request = spec.buildRequests(bidRequests, mockBidderRequest);
+          expect(request[0].data.user.ext.eids).to.eql(eids);
         });
 
         it(`when no user ids are available, it should not send any extended ids`, function () {
diff --git a/test/spec/modules/prebidServerBidAdapter_spec.js b/test/spec/modules/prebidServerBidAdapter_spec.js
index 46d7b313f3a..9769c2010df 100644
--- a/test/spec/modules/prebidServerBidAdapter_spec.js
+++ b/test/spec/modules/prebidServerBidAdapter_spec.js
@@ -2065,34 +2065,36 @@ describe('S2S Adapter', function () {
       });
     });
 
-    it('when userId is defined on bids, it\'s properties should be copied to user.ext.tpid properties', function () {
-      let consentConfig = { s2sConfig: CONFIG };
-      config.setConfig(consentConfig);
-
-      let userIdBidRequest = utils.deepClone(BID_REQUESTS);
-      userIdBidRequest[0].bids[0].userId = {
-        criteoId: '44VmRDeUE3ZGJ5MzRkRVJHU3BIUlJ6TlFPQUFU',
-        tdid: 'abc123',
-        pubcid: '1234',
-        parrableId: { eid: '01.1563917337.test-eid' },
-        lipb: {
-          lipbid: 'li-xyz',
-          segments: ['segA', 'segB']
-        },
-        idl_env: '0000-1111-2222-3333',
-        id5id: {
-          uid: '11111',
-          ext: {
-            linkType: 'some-link-type'
+    it('should pass user.ext.eids from FPD', function () {
+      config.setConfig({s2sConfig: CONFIG});
+      const req = {
+        ...REQUEST,
+        ortb2Fragments: {
+          global: {
+            user: {
+              ext: {
+                eids: [{id: 1}, {id: 2}]
+              }
+            }
+          },
+          bidder: {
+            appnexus: {
+              user: {
+                ext: {
+                  eids: [{id: 3}]
+                }
+              }
+            }
           }
         }
-      };
-      userIdBidRequest[0].bids[0].userIdAsEids = [{id: 1}, {id: 2}];
-
-      adapter.callBids(REQUEST, userIdBidRequest, addBidResponse, done, ajax);
-      let requestBid = JSON.parse(server.requests[0].requestBody);
-      expect(typeof requestBid.user.ext.eids).is.equal('object');
-      expect(requestBid.user.ext.eids).to.eql([{id: 1}, {id: 2}]);
+      }
+      adapter.callBids(req, BID_REQUESTS, addBidResponse, done, ajax);
+      const payload = JSON.parse(server.requests[0].requestBody);
+      expect(payload.user.ext.eids).to.eql([{id: 1}, {id: 2}]);
+      expect(payload.ext.prebid.bidderconfig).to.eql([{
+        bidders: ['appnexus'],
+        config: {ortb2: {user: {ext: {eids: [{id: 3}]}}}}
+      }]);
     });
 
     it('when config \'currency.adServerCurrency\' value is a string: ORTB has property \'cur\' value set to a single item array', function () {
diff --git a/test/spec/modules/pulsepointBidAdapter_spec.js b/test/spec/modules/pulsepointBidAdapter_spec.js
index da8b6d8473a..5b63e201e42 100644
--- a/test/spec/modules/pulsepointBidAdapter_spec.js
+++ b/test/spec/modules/pulsepointBidAdapter_spec.js
@@ -3,6 +3,9 @@ import {expect} from 'chai';
 import {spec} from 'modules/pulsepointBidAdapter.js';
 import {syncAddFPDToBidderRequest} from '../../helpers/fpd.js';
 import {deepClone} from '../../../src/utils';
+import 'modules/consentManagementTcf.js';
+import 'modules/consentManagementUsp.js';
+import 'modules/schain.js';
 
 describe('PulsePoint Adapter Tests', function () {
   const slotConfigs = [{
@@ -484,22 +487,33 @@ describe('PulsePoint Adapter Tests', function () {
 
   it('Verify common id parameters', function () {
     const bidRequests = deepClone(slotConfigs);
-    bidRequests[0].userIdAsEids = [{
-      source: 'pubcid.org',
-      uids: [{
-        id: 'userid_pubcid'
-      }]
-    }, {
-      source: 'adserver.org',
-      uids: [{
-        id: 'userid_ttd',
-        ext: {
-          rtiPartner: 'TDID'
+    const eids = [
+      {
+        source: 'pubcid.org',
+        uids: [{
+          id: 'userid_pubcid'
+        }]
+      }, {
+        source: 'adserver.org',
+        uids: [{
+          id: 'userid_ttd',
+          ext: {
+            rtiPartner: 'TDID'
+          }
+        }]
+      }
+    ];
+    const br = {
+      ...bidderRequest,
+      ortb2: {
+        user: {
+          ext: {
+            eids
+          }
         }
-      }]
+      }
     }
-    ];
-    const request = spec.buildRequests(bidRequests, syncAddFPDToBidderRequest(bidderRequest));
+    const request = spec.buildRequests(bidRequests, syncAddFPDToBidderRequest(br));
     expect(request).to.be.not.null;
     expect(request.data).to.be.not.null;
     const ortbRequest = request.data;
@@ -507,7 +521,7 @@ describe('PulsePoint Adapter Tests', function () {
     expect(ortbRequest.user).to.not.be.undefined;
     expect(ortbRequest.user.ext).to.not.be.undefined;
     expect(ortbRequest.user.ext.eids).to.not.be.undefined;
-    expect(ortbRequest.user.ext.eids).to.deep.equal(bidRequests[0].userIdAsEids);
+    expect(ortbRequest.user.ext.eids).to.deep.equal(eids);
   });
 
   it('Verify user level first party data', function () {
diff --git a/test/spec/modules/r2b2BidAdapter_spec.js b/test/spec/modules/r2b2BidAdapter_spec.js
index b94b400a71d..63850b78c40 100644
--- a/test/spec/modules/r2b2BidAdapter_spec.js
+++ b/test/spec/modules/r2b2BidAdapter_spec.js
@@ -420,7 +420,7 @@ describe('R2B2 adapter', function () {
           ],
         },
       ];
-      bids[0].userIdAsEids = eidsArray;
+      bidderRequest.ortb2 = {user: {ext: {eids: eidsArray}}}
       let requests = spec.buildRequests(bids, bidderRequest);
       let request = requests[0];
       let eids = request.data.user.ext.eids;
diff --git a/test/spec/modules/rubiconBidAdapter_spec.js b/test/spec/modules/rubiconBidAdapter_spec.js
index a5d25da9123..0856dc2571b 100644
--- a/test/spec/modules/rubiconBidAdapter_spec.js
+++ b/test/spec/modules/rubiconBidAdapter_spec.js
@@ -272,7 +272,7 @@ describe('the rubicon adapter', function () {
       }],
       criteoId: '1111',
     };
-    bid.userIdAsEids = [
+    const eids = [
       {
         'source': 'liveintent.com',
         'uids': [
@@ -347,6 +347,7 @@ describe('the rubicon adapter', function () {
         ]
       }
     ];
+    bidderRequest.ortb2 = {user: {ext: {eids}}};
     return bidderRequest;
   }
 
diff --git a/test/spec/modules/trafficgateBidAdapter_spec.js b/test/spec/modules/trafficgateBidAdapter_spec.js
index 7fbc566d375..192497f9c8d 100644
--- a/test/spec/modules/trafficgateBidAdapter_spec.js
+++ b/test/spec/modules/trafficgateBidAdapter_spec.js
@@ -1001,10 +1001,9 @@ describe('TrafficgateOpenxRtbAdapter', function () {
             bidId: 'test-bid-id-1',
             bidderRequestId: 'test-bid-request-1',
             auctionId: 'test-auction-1',
-            userIdAsEids: userIdAsEids
           }];
           // enrich bid request with userId key/value
-
+          mockBidderRequest.ortb2 = {user: {ext: {eids: userIdAsEids}}}
           const request = spec.buildRequests(bidRequestsWithUserId, mockBidderRequest);
           expect(request[0].data.user.ext.eids).to.eql(userIdAsEids);
         });
diff --git a/test/spec/modules/uid2IdSystem_helpers.js b/test/spec/modules/uid2IdSystem_helpers.js
index cf60b123c66..44a3b374999 100644
--- a/test/spec/modules/uid2IdSystem_helpers.js
+++ b/test/spec/modules/uid2IdSystem_helpers.js
@@ -1,6 +1,6 @@
 import {setConsentConfig} from 'modules/consentManagementTcf.js';
 import {server} from 'test/mocks/xhr.js';
-import {coreStorage, requestBidsHook} from 'modules/userId/index.js';
+import {coreStorage, startAuctionHook} from 'modules/userId/index.js';
 
 const msIn12Hours = 60 * 60 * 12 * 1000;
 const expireCookieDate = 'Thu, 01 Jan 1970 00:00:01 GMT';
@@ -19,7 +19,7 @@ export const runAuction = async () => {
     bids: [{bidder: 'sampleBidder', params: {placementId: 'banner-only-bidder'}}]
   }];
   return new Promise(function(resolve) {
-    requestBidsHook(function() {
+    startAuctionHook(function() {
       resolve(adUnits[0].bids[0]);
     }, {adUnits});
   });
diff --git a/test/spec/modules/userId_spec.js b/test/spec/modules/userId_spec.js
index 2f28df47667..3e659c867cf 100644
--- a/test/spec/modules/userId_spec.js
+++ b/test/spec/modules/userId_spec.js
@@ -2,12 +2,12 @@ import {
   attachIdSystem,
   auctionDelay,
   coreStorage,
-  dep,
+  dep, enrichEids,
   findRootDomain,
   getConsentHash, getValidSubmoduleConfigs,
   init,
   PBJS_USER_ID_OPTOUT_NAME,
-  requestBidsHook,
+  startAuctionHook,
   requestDataDeletion,
   setStoredValue,
   setSubmoduleRegistry,
@@ -70,6 +70,7 @@ describe('User ID', function () {
       decode(v) {
         return v;
       },
+      primaryIds: [],
       aliasName,
       eids
     }
@@ -136,7 +137,7 @@ describe('User ID', function () {
   function runBidsHook(...args) {
     startDelay = delay();
 
-    const result = requestBidsHook(...args, {delay: startDelay});
+    const result = startAuctionHook(...args, {delay: startDelay});
     return new Promise((resolve) => setTimeout(() => resolve(result)));
   }
 
@@ -176,6 +177,10 @@ describe('User ID', function () {
     config.resetConfig();
   });
 
+  after(() => {
+    init(config);
+  })
+
   describe('GVL IDs', () => {
     beforeEach(() => {
       sinon.stub(GDPR_GVLIDS, 'register');
@@ -1114,7 +1119,7 @@ describe('User ID', function () {
         // simulate an infinite `auctionDelay`; refreshing should still allow the auction to continue
         // as soon as ID submodules have completed init
         startInit();
-        requestBidsHook(() => {
+        startAuctionHook(() => {
           done();
         }, {adUnits: [getAdUnitMock()]}, {delay: delay()});
         getGlobal().refreshUserIds();
@@ -1126,7 +1131,7 @@ describe('User ID', function () {
 
       it('should continue the auction when init fails', (done) => {
         startInit();
-        requestBidsHook(() => {
+        startAuctionHook(() => {
           done();
         },
         {adUnits: [getAdUnitMock()]},
@@ -1634,7 +1639,7 @@ describe('User ID', function () {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.mid');
               expect(bid.userId.mid).to.equal('1234');
-              expect(bid.userIdAsEids.length).to.equal(0);// "mid" is an un-known submodule for USER_IDS_CONFIG in eids.js
+              expect(bid.userIdAsEids).to.not.exist;// "mid" is an un-known submodule for USER_IDS_CONFIG in eids.js
             });
           });
 
@@ -1728,13 +1733,46 @@ describe('User ID', function () {
       });
     });
 
-    describe('Request bids hook appends userId to bid objs in adapters', function () {
+    describe('Start auction hook appends userId to bid objs in adapters', function () {
       let adUnits;
 
       beforeEach(function () {
         adUnits = [getAdUnitMock()];
       });
 
+      it('should include pub-provided eids in userIdAsEids', (done) => {
+        init(config);
+        setSubmoduleRegistry([createMockIdSubmodule('mockId', {id: {mockId: 'id'}}, null, {mockId: {source: 'mockid.com', atype: 1}})]);
+        config.setConfig({
+          userSync: {
+            userIds: [
+              {name: 'mockId'}
+            ]
+          }
+        });
+        startAuctionHook(({adUnits}) => {
+          adUnits[0].bids.forEach(bid => {
+            expect(bid.userIdAsEids.find(eid => eid.source === 'mockid.com')).to.exist;
+            const bidderEid = bid.userIdAsEids.find(eid => eid.bidder === 'pub-provided');
+            expect(bidderEid != null).to.eql(bid.bidder === 'sampleBidder');
+            expect(bid.userIdAsEids.find(eid => eid.id === 'pub-provided')).to.exist;
+          })
+          done();
+        }, {
+          adUnits,
+          ortb2Fragments: {
+            global: {
+              user: {ext: {eids: [{id: 'pub-provided'}]}}
+            },
+            bidder: {
+              sampleBidder: {
+                user: {ext: {eids: [{bidder: 'pub-provided'}]}}
+              }
+            }
+          }
+        })
+      })
+
       it('test hook from pubcommonid cookie', function (done) {
         coreStorage.setCookie('pubcid', 'testpubcid', (new Date(Date.now() + 100000).toUTCString()));
 
@@ -1742,7 +1780,7 @@ describe('User ID', function () {
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig(getConfigMock(['pubCommonId', 'pubcid', 'cookie']));
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubcid');
@@ -1767,7 +1805,7 @@ describe('User ID', function () {
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig(getConfigMock(['pubCommonId', 'pubcid', 'html5']));
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubcid');
@@ -1794,7 +1832,7 @@ describe('User ID', function () {
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig(getConfigMock(['pubCommonId', 'pubcid', 'cookie&html5']));
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubcid');
@@ -1822,7 +1860,7 @@ describe('User ID', function () {
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig(getConfigMock(['pubCommonId', 'pubcid', 'cookie&html5']));
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubcid');
@@ -1848,7 +1886,7 @@ describe('User ID', function () {
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig(getConfigMock(['pubCommonId', 'pubcid', 'cookie&html5']));
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubcid');
@@ -1871,133 +1909,18 @@ describe('User ID', function () {
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig(getConfigValueMock('pubCommonId', {'pubcidvalue': 'testpubcidvalue'}));
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubcidvalue');
               expect(bid.userId.pubcidvalue).to.equal('testpubcidvalue');
-              expect(bid.userIdAsEids.length).to.equal(0);// "pubcidvalue" is an un-known submodule for USER_IDS_CONFIG in eids.js
+              expect(bid.userIdAsEids).to.not.exist; // "pubcidvalue" is an un-known submodule for USER_IDS_CONFIG in eids.js
             });
           });
           done();
         }, {adUnits});
       });
 
-      it('eidPermissions fun with bidders', function (done) {
-        coreStorage.setCookie('pubcid', 'test222', (new Date(Date.now() + 5000).toUTCString()));
-
-        init(config);
-        setSubmoduleRegistry([sharedIdSystemSubmodule]);
-        let eidPermissions;
-        getPrebidInternal().setEidPermissions = function (newEidPermissions) {
-          eidPermissions = newEidPermissions;
-        }
-        config.setConfig({
-          userSync: {
-            syncDelay: 0,
-            userIds: [
-              {
-                name: 'pubCommonId',
-                bidders: [
-                  'sampleBidder'
-                ],
-                storage: {
-                  type: 'cookie',
-                  name: 'pubcid',
-                  expires: 28
-                }
-              }
-            ]
-          }
-        });
-
-        requestBidsHook(function () {
-          expect(eidPermissions).to.deep.equal(
-            [
-              {
-                bidders: [
-                  'sampleBidder'
-                ],
-                source: 'pubcid.org'
-              }
-            ]
-          );
-          adUnits.forEach(unit => {
-            unit.bids.forEach(bid => {
-              if (bid.bidder === 'sampleBidder') {
-                expect(bid).to.have.deep.nested.property('userId.pubcid');
-                expect(bid.userId.pubcid).to.equal('test222');
-                expect(bid.userIdAsEids[0]).to.deep.equal({
-                  source: 'pubcid.org',
-                  uids: [
-                    {
-                      id: 'test222',
-                      atype: 1
-                    }
-                  ]
-                });
-              }
-              if (bid.bidder === 'anotherSampleBidder') {
-                expect(bid).to.not.have.deep.nested.property('userId.pubcid');
-                expect(bid).to.not.have.property('userIdAsEids');
-              }
-            });
-          });
-          coreStorage.setCookie('pubcid', '', EXPIRED_COOKIE_DATE);
-          getPrebidInternal().setEidPermissions = undefined;
-          done();
-        }, {adUnits});
-      });
-
-      it('eidPermissions fun without bidders', function (done) {
-        coreStorage.setCookie('pubcid', 'test222', new Date(Date.now() + 5000).toUTCString());
-
-        init(config);
-        setSubmoduleRegistry([sharedIdSystemSubmodule]);
-        let eidPermissions;
-        getPrebidInternal().setEidPermissions = function (newEidPermissions) {
-          eidPermissions = newEidPermissions;
-        }
-        config.setConfig({
-          userSync: {
-            syncDelay: 0,
-            userIds: [
-              {
-                name: 'pubCommonId',
-                storage: {
-                  type: 'cookie',
-                  name: 'pubcid',
-                  expires: 28
-                }
-              }
-            ]
-          }
-        });
-
-        requestBidsHook(function () {
-          expect(eidPermissions).to.deep.equal(
-            []
-          );
-          adUnits.forEach(unit => {
-            unit.bids.forEach(bid => {
-              expect(bid).to.have.deep.nested.property('userId.pubcid');
-              expect(bid.userId.pubcid).to.equal('test222');
-              expect(bid.userIdAsEids[0]).to.deep.equal({
-                source: 'pubcid.org',
-                uids: [
-                  {
-                    id: 'test222',
-                    atype: 1
-                  }]
-              });
-            });
-          });
-          getPrebidInternal().setEidPermissions = undefined;
-          coreStorage.setCookie('pubcid', '', EXPIRED_COOKIE_DATE);
-          done();
-        }, {adUnits});
-      });
-
       it('test hook from pubProvidedId config params', function (done) {
         init(config);
         setSubmoduleRegistry([pubProvidedIdSubmodule]);
@@ -2041,7 +1964,7 @@ describe('User ID', function () {
           }
         });
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               expect(bid).to.have.deep.nested.property('userId.pubProvidedId');
@@ -2126,7 +2049,7 @@ describe('User ID', function () {
           }
         });
 
-        requestBidsHook(function () {
+        startAuctionHook(function () {
           adUnits.forEach(unit => {
             unit.bids.forEach(bid => {
               // check PubCommonId id data was copied to bid
@@ -2181,7 +2104,7 @@ describe('User ID', function () {
               }))
             }
           });
-          requestBidsHook((req) => {
+          startAuctionHook((req) => {
             const activeIds = req.adUnits.flatMap(au => au.bids).flatMap(bid => Object.keys(bid.userId));
             expect(Array.from(new Set(activeIds))).to.have.members([MOCK_IDS[1]]);
             done();
@@ -2514,7 +2437,7 @@ describe('User ID', function () {
         expect(typeof (getGlobal()).getEncryptedEidsForSource).to.equal('function');
       });
 
-      it('pbjs.getEncryptedEidsForSource should return the string without encryption if encryption is false', (done) => {
+      it('pbjs.getEncryptedEidsForSource should return the string without encryption if encryption is false', () => {
         init(config);
         setSubmoduleRegistry([sharedIdSystemSubmodule]);
         config.setConfig({
@@ -2536,43 +2459,42 @@ describe('User ID', function () {
           },
         });
         const encrypt = false;
-        (getGlobal()).getEncryptedEidsForSource(signalSources[0], encrypt).then((data) => {
+        return (getGlobal()).getEncryptedEidsForSource(signalSources[0], encrypt).then((data) => {
           let users = (getGlobal()).getUserIdsAsEids();
           expect(data).to.equal(users[0].uids[0].id);
-          done();
-        }).catch(done);
+        })
       });
 
       it('pbjs.getEncryptedEidsForSource should return prioritized id as non-encrypted string', (done) => {
         init(config);
-        setSubmoduleRegistry([
-          createMockIdSubmodule('mockId1Module', {id: {uid2: {id: 'uid2_value'}}}),
-          createMockIdSubmodule('mockId2Module', {id: {pubcid: 'pubcid_value', lipb: {lipbid: 'lipbid_value_from_mockId2Module'}}}),
-          createMockIdSubmodule('mockId3Module', {id: {uid2: {id: 'uid2_value_from_mockId3Module'}, pubcid: 'pubcid_value_from_mockId3Module', lipb: {lipbid: 'lipbid_value'}, merkleId: {id: 'merkleId_value_from_mockId3Module'}}}, null, {
-            uid2: {
-              source: 'uidapi.com',
-              getValue(data) {
-                return data.id
-              }
-            },
-            pubcid: {
-              source: 'pubcid.org',
-            },
-            lipb: {
-              source: 'liveintent.com',
-              getValue(data) {
-                return data.lipbid
-              }
+        const EIDS = {
+          uid2: {
+            source: 'uidapi.com',
+            getValue(data) {
+              return data.id
             }
-          }),
-          createMockIdSubmodule('mockId4Module', {id: {merkleId: {id: 'merkleId_value'}}}, null, {
-            merkleId: {
-              source: 'merkleinc.com',
-              getValue(data) {
-                return data.id
-              }
+          },
+          pubcid: {
+            source: 'pubcid.org',
+          },
+          lipb: {
+            source: 'liveintent.com',
+            getValue(data) {
+              return data.lipbid
             }
-          })
+          },
+          merkleId: {
+            source: 'merkleinc.com',
+            getValue(data) {
+              return data.id
+            }
+          }
+        }
+        setSubmoduleRegistry([
+          createMockIdSubmodule('mockId1Module', {id: {uid2: {id: 'uid2_value'}}}, null, EIDS),
+          createMockIdSubmodule('mockId2Module', {id: {pubcid: 'pubcid_value', lipb: {lipbid: 'lipbid_value_from_mockId2Module'}}}, null, EIDS),
+          createMockIdSubmodule('mockId3Module', {id: {uid2: {id: 'uid2_value_from_mockId3Module'}, pubcid: 'pubcid_value_from_mockId3Module', lipb: {lipbid: 'lipbid_value'}, merkleId: {id: 'merkleId_value_from_mockId3Module'}}}, null, EIDS),
+          createMockIdSubmodule('mockId4Module', {id: {merkleId: {id: 'merkleId_value'}}}, null, EIDS)
         ]);
         config.setConfig({
           userSync: {
@@ -2717,4 +2639,246 @@ describe('User ID', function () {
       });
     })
   });
+
+  describe('enrichEids', () => {
+    let idValues;
+
+    function mockIdSubmodule(key, ...extraKeys) {
+      return {
+        name: `${key}Module`,
+        decode(v) { return v },
+        getId() {
+          return {
+            id: Object.fromEntries(
+              idValues[key]?.map(mod => [mod, key === mod ? `${key}_value` : `${mod}_value_from_${key}Module`])
+            )
+          }
+        },
+        primaryIds: [key],
+        eids: {
+          [key]: {
+            source: `${key}.com`,
+            atype: 1,
+          },
+          ...Object.fromEntries(extraKeys.map(extraKey => [extraKey, {
+            source: `${extraKey}.com`,
+            atype: 1,
+            getUidExt() {
+              return {provider: `${key}Module`}
+            }
+          }]))
+        }
+      }
+    }
+
+    beforeEach(() => {
+      idValues = {
+        mockId1: ['mockId1'],
+        mockId2: ['mockId2', 'mockId3'],
+        mockId3: ['mockId1', 'mockId2', 'mockId3', 'mockId4'],
+        mockId4: ['mockId4']
+      }
+      init(config);
+
+      setSubmoduleRegistry([
+        mockIdSubmodule('mockId1'),
+        mockIdSubmodule('mockId2', 'mockId3'),
+        mockIdSubmodule('mockId3', 'mockId1', 'mockId2', 'mockId4'),
+        mockIdSubmodule('mockId4')
+      ]);
+    })
+
+    function enrich({global = {}, bidder = {}} = {}) {
+      return getGlobal().getUserIdsAsync().then(() => {
+        enrichEids({global, bidder});
+        return {global, bidder};
+      })
+    }
+
+    function eidsFrom(nameFromModuleMapping) {
+      return Object.entries(nameFromModuleMapping).map(([key, module]) => {
+        const owner = `${key}Module` === module
+        const uid = {
+          id: owner ? `${key}_value` : `${key}_value_from_${module}`,
+          atype: 1,
+        };
+        if (!owner) {
+          uid.ext = {provider: module}
+        }
+        return {
+          source: `${key}.com`,
+          uids: [uid]
+        }
+      })
+    }
+
+    function bidderEids(bidderMappings) {
+      return Object.fromEntries(
+        Object.entries(bidderMappings).map(([bidder, mapping]) => [bidder, {user: {ext: {eids: eidsFrom(mapping)}}}])
+      )
+    }
+
+    it('should use lower-priority module if higher priority module cannot provide an id', () => {
+      idValues.mockId3 = []
+      config.setConfig({
+        userSync: {
+          idPriority: {
+            mockId1: ['mockId3Module', 'mockId1Module']
+          },
+          userIds: [
+            { name: 'mockId1Module' },
+            { name: 'mockId3Module' },
+          ]
+        }
+      });
+      return enrich().then(({global}) => {
+        expect(global.user.ext.eids).to.eql(eidsFrom({
+          mockId1: 'mockId1Module'
+        }))
+      });
+    });
+
+    it('should not choke if no id is available for a module', () => {
+      idValues.mockId1 = []
+      config.setConfig({
+        userSync: {
+          userIds: [
+            { name: 'mockId1Module' },
+          ]
+        }
+      });
+      return enrich().then(({global}) => {
+        expect(global.user?.ext?.eids).to.not.exist;
+      });
+    });
+
+    it('should add EIDs that are not bidder-restricted', () => {
+      config.setConfig({
+        userSync: {
+          idPriority: {
+            mockId1: ['mockId3Module', 'mockId1Module'],
+            mockId4: ['mockId4Module', 'mockId3Module']
+          },
+          userIds: [
+            { name: 'mockId1Module' },
+            { name: 'mockId2Module' },
+            { name: 'mockId3Module' },
+            { name: 'mockId4Module' },
+          ]
+        }
+      });
+      return enrich().then(({global}) => {
+        expect(global.user.ext.eids).to.eql(eidsFrom({
+          mockId1: 'mockId3Module',
+          mockId2: 'mockId2Module',
+          mockId3: 'mockId3Module',
+          mockId4: 'mockId4Module'
+        }));
+      });
+    });
+
+    it('should separate bidder-restricted eids', () => {
+      config.setConfig({
+        userSync: {
+          userIds: [
+            { name: 'mockId1Module', bidders: ['bidderA', 'bidderB'] },
+            { name: 'mockId4Module' },
+          ]
+        }
+      });
+      return enrich().then(({global, bidder}) => {
+        expect(global.user.ext.eids).to.eql(eidsFrom({
+          mockId4: 'mockId4Module'
+        }));
+        [bidder.bidderA, bidder.bidderB].forEach(bidderCfg => {
+          expect(bidderCfg.user.ext.eids).to.eql(eidsFrom({
+            mockId1: 'mockId1Module'
+          }))
+        })
+      });
+    })
+
+    it('should exclude bidder-unrestricted IDs that conflict for some bidders', () => {
+      config.setConfig({
+        userSync: {
+          idPriority: {
+            mockId1: ['mockId1Module', 'mockId3Module'],
+          },
+          userIds: [
+            { name: 'mockId1Module', bidders: ['bidderA'] },
+            { name: 'mockId3Module' },
+          ]
+        }
+      });
+      return enrich().then(({global, bidder}) => {
+        expect(global.user.ext.eids).to.eql(eidsFrom({
+          mockId2: 'mockId3Module',
+          mockId3: 'mockId3Module',
+          mockId4: 'mockId3Module'
+        }));
+        expect(bidder).to.eql({});
+      });
+    });
+
+    it('should provide bidder-specific IDs, even when they conflict across bidders', () => {
+      config.setConfig({
+        userSync: {
+          idPriority: {
+            mockId1: ['mockId1Module', 'mockId3Module'],
+          },
+          userIds: [
+            { name: 'mockId1Module', bidders: ['bidderA'] },
+            { name: 'mockId3Module', bidders: ['bidderB'] },
+          ]
+        }
+      });
+      return enrich().then(({global, bidder}) => {
+        expect(global.user?.ext?.eids).to.not.exist;
+        expect(bidder).to.eql(bidderEids({
+          bidderA: {
+            mockId1: 'mockId1Module'
+          },
+          bidderB: {
+            mockId1: 'mockId1Module',
+            mockId2: 'mockId3Module',
+            mockId3: 'mockId3Module',
+            mockId4: 'mockId3Module'
+          }
+        }));
+      });
+    });
+
+    it('should not override pub-provided EIDS', () => {
+      config.setConfig({
+        userSync: {
+          auctionDelay: 10,
+          userIds: [
+            { name: 'mockId1Module', bidders: ['bidderA', 'bidderB'] },
+            { name: 'mockId4Module' },
+          ]
+        }
+      });
+      const globalEids = [{pub: 'provided'}];
+      const bidderAEids = [{bidder: 'A'}]
+      const fpd = {
+        global: {user: {ext: {eids: globalEids}}},
+        bidder: {
+          bidderA: {
+            user: {ext: {eids: bidderAEids}}
+          }
+        }
+      }
+      return enrich(fpd).then(({global, bidder}) => {
+        expect(global.user.ext.eids).to.eql(globalEids.concat(eidsFrom({
+          mockId4: 'mockId4Module'
+        })));
+        expect(bidder.bidderA.user.ext.eids).to.eql(bidderAEids.concat(eidsFrom({
+          mockId1: 'mockId1Module'
+        })));
+        expect(bidder.bidderB.user.ext.eids).to.eql(eidsFrom({
+          mockId1: 'mockId1Module'
+        }));
+      });
+    })
+  });
 });
diff --git a/test/spec/modules/zeotapIdPlusIdSystem_spec.js b/test/spec/modules/zeotapIdPlusIdSystem_spec.js
index 67e2939a97d..5b2f4e15129 100644
--- a/test/spec/modules/zeotapIdPlusIdSystem_spec.js
+++ b/test/spec/modules/zeotapIdPlusIdSystem_spec.js
@@ -1,7 +1,7 @@
 import { expect } from 'chai';
 import {find} from 'src/polyfill.js';
 import { config } from 'src/config.js';
-import {attachIdSystem, init, requestBidsHook, setSubmoduleRegistry} from 'modules/userId/index.js';
+import {attachIdSystem, init, startAuctionHook, setSubmoduleRegistry} from 'modules/userId/index.js';
 import { storage, getStorage, zeotapIdPlusSubmodule } from 'modules/zeotapIdPlusIdSystem.js';
 import * as storageManager from 'src/storageManager.js';
 import {MODULE_TYPE_UID} from '../../../src/activities/modules.js';
@@ -176,7 +176,7 @@ describe('Zeotap ID System', function() {
     });
 
     it('when a stored Zeotap ID exists it is added to bids', function(done) {
-      requestBidsHook(function() {
+      startAuctionHook(function() {
         adUnits.forEach(unit => {
           unit.bids.forEach(bid => {
             expect(bid).to.have.deep.nested.property('userId.IDP');
diff --git a/test/spec/ortbConverter/userId_spec.js b/test/spec/ortbConverter/userId_spec.js
deleted file mode 100644
index 2084cb0cfae..00000000000
--- a/test/spec/ortbConverter/userId_spec.js
+++ /dev/null
@@ -1,54 +0,0 @@
-import {setOrtbUserExtEids} from '../../../modules/userId/index.js';
-
-describe('pbjs - ortb user eids', () => {
-  it('sets user.ext.eids from request', () => {
-    const req = {};
-    setOrtbUserExtEids(req, {}, {
-      bidRequests: [
-        {
-          userIdAsEids: [{e: 'id'}]
-        }
-      ]
-    });
-    expect(req.user.ext.eids).to.eql([{e: 'id'}]);
-  });
-
-  it('should not override eids from fpd', () => {
-    const req = {
-      user: {
-        ext: {
-          eids: [{existing: 'id'}]
-        }
-      }
-    };
-    setOrtbUserExtEids(req, {}, {
-      bidRequests: [
-        {
-          userIdAsEids: [{nw: 'id'}]
-        }
-      ]
-    });
-    expect(req.user.ext.eids).to.eql([
-      {nw: 'id'},
-      {existing: 'id'},
-    ])
-  })
-
-  it('has no effect if requests have no eids', () => {
-    const req = {};
-    setOrtbUserExtEids(req, {}, [{}]);
-    expect(req).to.eql({});
-  })
-
-  it('has no effect if user.ext.eids is an empty array', () => {
-    const req = {};
-    setOrtbUserExtEids(req, {}, {
-      bidRequests: [
-        {
-          userIdAsEids: []
-        }
-      ]
-    });
-    expect(req).to.eql({});
-  });
-})
diff --git a/test/spec/unit/pbjs_api_spec.js b/test/spec/unit/pbjs_api_spec.js
index 558fb17dc42..0c450c7f1ae 100644
--- a/test/spec/unit/pbjs_api_spec.js
+++ b/test/spec/unit/pbjs_api_spec.js
@@ -1916,7 +1916,7 @@ describe('Unit: Prebid Module', function () {
     });
 
     it('passes ortb2 fragments to createAuction', () => {
-      const ortb2Fragments = {};
+      const ortb2Fragments = {global: {}, bidder: {}};
       pbjsModule.startAuction({
         adUnits: [{
           code: 'au',