diff --git a/src/util.cpp b/src/util.cpp
index 76a27002719..d6a113095da 100644
--- a/src/util.cpp
+++ b/src/util.cpp
@@ -389,7 +389,7 @@ bool ParseMoney(const char* pszIn, int64& nRet)
     for (; *p; p++)
         if (!isspace(*p))
             return false;
-    if (strWhole.size() > 14)
+    if (strWhole.size() > 10) // guard against 63 bit overflow
         return false;
     if (nUnits < 0 || nUnits > COIN)
         return false;