diff --git a/specs/core/0_beacon-chain.md b/specs/core/0_beacon-chain.md
index bcd0737c3..8a90bc2f4 100644
--- a/specs/core/0_beacon-chain.md
+++ b/specs/core/0_beacon-chain.md
@@ -668,7 +668,6 @@ def shuffle_index(index: ValidatorIndex, index_count: uint64, seed: Hash) -> Val
     Return the shuffled validator index corresponding to ``seed`` (and ``index_count``).
     """
     assert index < index_count
-    assert index_count <= 2**40
 
     # Swap or not (https://link.springer.com/content/pdf/10.1007%2F978-3-642-32009-5_1.pdf)
     # See the 'generalized domain' algorithm on page 3