diff --git a/contracts/amm/spread/SpreadCloseSwapService.sol b/contracts/amm/spread/SpreadCloseSwapService.sol
index 7de46a1cf..b6e1117a4 100644
--- a/contracts/amm/spread/SpreadCloseSwapService.sol
+++ b/contracts/amm/spread/SpreadCloseSwapService.sol
@@ -79,16 +79,26 @@ contract SpreadCloseSwapService is ISpreadCloseSwapService {
                 actualTimeWeightedNotionalToSave = 0;
                 swapTimePast = 0;
             }
+            // @dev Ensure denominator is at least 1% of tenor to prevent near-zero division
+            // that could cause uint96 overflow in SpreadStorageLibs.saveTimeWeightedNotionalForAssetAndTenor
+            uint256 denominator = tenorInSeconds - swapTimePast;
+            uint256 minDenominator = tenorInSeconds / 100;
+            if (minDenominator == 0) {
+                minDenominator = 1;
+            }
+            if (denominator < minDenominator) {
+                denominator = minDenominator;
+            }
             if (direction == 0) {
                 timeWeightedNotional.lastUpdateTimePayFixed = lastOpenSwap.openSwapTimestamp;
                 timeWeightedNotional.timeWeightedNotionalPayFixed =
                     (actualTimeWeightedNotionalToSave * tenorInSeconds) /
-                    (tenorInSeconds - swapTimePast);
+                    denominator;
             } else {
                 timeWeightedNotional.lastUpdateTimeReceiveFixed = lastOpenSwap.openSwapTimestamp;
                 timeWeightedNotional.timeWeightedNotionalReceiveFixed =
                     (actualTimeWeightedNotionalToSave * tenorInSeconds) /
-                    (tenorInSeconds - swapTimePast);
+                    denominator;
             }
         } else {
             if (direction == 0) {