diff --git a/compiler-builtins/src/int/big.rs b/compiler-builtins/src/int/big.rs
index 61f1349d..1402efb8 100644
--- a/compiler-builtins/src/int/big.rs
+++ b/compiler-builtins/src/int/big.rs
@@ -65,7 +65,7 @@ impl MinInt for i256 {
     const ZERO: Self = Self([0u64; 4]);
     const ONE: Self = Self([1, 0, 0, 0]);
     const MIN: Self = Self([0, 0, 0, 1 << 63]);
-    const MAX: Self = Self([u64::MAX, u64::MAX, u64::MAX, u64::MAX << 1]);
+    const MAX: Self = Self([u64::MAX, u64::MAX, u64::MAX, u64::MAX >> 1]);
 }
 
 macro_rules! impl_common {
diff --git a/libm/src/math/support/big.rs b/libm/src/math/support/big.rs
index f24c063c..8a52d86c 100644
--- a/libm/src/math/support/big.rs
+++ b/libm/src/math/support/big.rs
@@ -83,7 +83,7 @@ impl MinInt for i256 {
     };
     const MAX: Self = Self {
         lo: u128::MAX,
-        hi: u128::MAX << 1,
+        hi: u128::MAX >> 1,
     };
 }