diff --git a/math/src/stableswap/tests/invariants.rs b/math/src/stableswap/tests/invariants.rs
index 1468a7887..a730aeda7 100644
--- a/math/src/stableswap/tests/invariants.rs
+++ b/math/src/stableswap/tests/invariants.rs
@@ -145,24 +145,3 @@ proptest! {
 		assert!(y >= reserve_a);
 	}
 }
-
-proptest! {
-	#![proptest_config(ProptestConfig::with_cases(1000))]
-	#[test]
-	fn round_trip_d_y_4(reserve_a in asset_reserve(),
-		reserve_b in asset_reserve(),
-		reserve_c in asset_reserve(),
-		reserve_e in asset_reserve(),
-		amp in amplification(),
-	) {
-		let ann = amp * 256u128;  // 4^4
-
-		let reserve_d = 0u128;
-
-		let d = calculate_d::<D_ITERATIONS>(&[reserve_a, reserve_b, reserve_c, reserve_d, reserve_e], ann).unwrap();
-		let y = calculate_y::<Y_ITERATIONS>(&[reserve_b, reserve_c, reserve_d, reserve_e], d, ann).unwrap();
-
-		assert!(y - 4 <= reserve_a);
-		assert!(y >= reserve_a);
-	}
-}
diff --git a/math/src/stableswap/tests/two_assets.rs b/math/src/stableswap/tests/two_assets.rs
index 4a95327f0..13dd98910 100644
--- a/math/src/stableswap/tests/two_assets.rs
+++ b/math/src/stableswap/tests/two_assets.rs
@@ -24,6 +24,12 @@ fn test_d_with_zero_reserves() {
 	assert_eq!(calculate_d::<D_ITERATIONS>(&reserves, 1), Some(0u128));
 }
 
+#[test]
+fn test_d_with_one_zero_reserves() {
+	let reserves = [1000u128, 0u128];
+	assert_eq!(calculate_d::<D_ITERATIONS>(&reserves, 1), None);
+}
+
 #[test]
 fn test_y_given_in() {
 	let reserves = [1000u128, 2000u128];
@@ -94,12 +100,12 @@ fn test_shares() {
 	let amp = 100u128;
 
 	let initial_reserves = &[0u128, 0u128];
-	let updated_reserves = &[1000 * ONE, 0u128];
+	let updated_reserves = &[1000 * ONE, 500u128];
 
 	let result = calculate_shares::<D_ITERATIONS>(initial_reserves, updated_reserves, amp, 0u128);
 
 	assert!(result.is_some());
-	assert_eq!(result.unwrap(), 1_000_000_000_000_000u128);
+	assert_eq!(result.unwrap(), 928031226918u128);
 }
 #[test]
 fn remove_one_asset_should_work() {