diff --git a/cbmc/proofs/poly_invntt_tomont/Makefile b/cbmc/proofs/poly_invntt_tomont/Makefile
index 110a37f26..211c0f5b9 100644
--- a/cbmc/proofs/poly_invntt_tomont/Makefile
+++ b/cbmc/proofs/poly_invntt_tomont/Makefile
@@ -36,7 +36,7 @@ FUNCTION_NAME = poly_invntt_tomont
 # EXPENSIVE = true
 
 # This function is large enough to need...
-CBMC_OBJECT_BITS = 12
+CBMC_OBJECT_BITS = 13
 
 # If you require access to a file-local ("static") function or object to conduct
 # your proof, set the following (and do not include the original source file