diff --git a/contracts/LoopringProtocol.sol b/contracts/LoopringProtocol.sol
index dc931a02..96997de9 100644
--- a/contracts/LoopringProtocol.sol
+++ b/contracts/LoopringProtocol.sol
@@ -85,7 +85,7 @@ contract LoopringProtocol {
     function cancelAllOrdersByTradingPair(
         address token1,
         address token2,
-        uint cutoff
+        uint    cutoff
         )
         external;
 
@@ -116,7 +116,7 @@ contract LoopringProtocol {
     function submitRing(
         address[5][]    addressesList,
         uint[6][]       valuesList,
-        uint8[]          optionList,
+        uint8[]         optionList,
         bytes[]         sigList,
         address         miner,
         uint8           feeSelections
diff --git a/contracts/LoopringProtocolImpl.sol b/contracts/LoopringProtocolImpl.sol
index 92c87a13..0c41e9ae 100644
--- a/contracts/LoopringProtocolImpl.sol
+++ b/contracts/LoopringProtocolImpl.sol
@@ -600,6 +600,7 @@ contract LoopringProtocolImpl is LoopringProtocol {
                     order.amountS < availableAmountS ?
                     order.amountS : availableAmountS
                 );
+                require(order.fillAmountS > 0, "fillAmountS is 0");
             }
         }
     }
@@ -842,6 +843,7 @@ contract LoopringProtocolImpl is LoopringProtocol {
                 order.fillAmountS = fillAmountB.mul(
                     order.rateS
                 ) / order.rateB;
+                require(order.fillAmountS > 0, "fillAmountS is 0");
 
                 newSmallestIdx = i;
             }
diff --git a/contracts/TokenTransferDelegateImpl.sol b/contracts/TokenTransferDelegateImpl.sol
index 583c5360..1d6c7782 100644
--- a/contracts/TokenTransferDelegateImpl.sol
+++ b/contracts/TokenTransferDelegateImpl.sol
@@ -195,14 +195,16 @@ contract TokenTransferDelegateImpl is TokenTransferDelegate, Claimable {
             // Here batch[i + 4] has been checked not to be 0.
             if (owner != prevOwner) {
                 amount = uint(batch[i + 4]);
-                require(
-                    ERC20(token).transferFrom(
-                        owner,
-                        prevOwner,
-                        amount
-                    ),
-                    "token transfer failure"
-                );
+                if (amount > 0) {
+                    require(
+                        ERC20(token).transferFrom(
+                            owner,
+                            prevOwner,
+                            amount
+                        ),
+                        "token transfer failure"
+                    );
+                }
 
                 if (tracker != 0x0) {
                     require(