diff --git a/lib/bcoin/tx.js b/lib/bcoin/tx.js
index 576c3bd2..9003f59b 100644
--- a/lib/bcoin/tx.js
+++ b/lib/bcoin/tx.js
@@ -957,24 +957,26 @@ TX.prototype.hasCoins = function hasCoins() {
 
 TX.prototype.fillCoins = function fillCoins(coins) {
   var total = 0;
-  var key, i, input, prevout;
+  var key, i, input, prevout, map, coin;
 
-  if ((coins instanceof bcoin.coin) || (coins instanceof bcoin.tx))
+  if ((coins instanceof bcoin.coin) || (coins instanceof TX))
     coins = [coins];
 
   if (Array.isArray(coins)) {
-    coins = coins.reduce(function(out, coin) {
+    map = {};
+    for (i = 0; i < coins.length; i++) {
+      coin = coins[i];
       if (coin instanceof TX) {
-        out[coin.hash('hex')] = coin;
+        map[coin.hash('hex')] = coin;
       } else if (coin instanceof bcoin.coin) {
         assert(typeof coin.hash === 'string');
         assert(typeof coin.index === 'number');
-        out[coin.hash + '/' + coin.index] = coin;
+        map[coin.hash + '/' + coin.index] = coin;
       } else {
         assert(false, 'Non-coin object passed to fillCoins.');
       }
-      return out;
-    }, {});
+    }
+    coins = map;
   }
 
   for (i = 0; i < this.inputs.length; i++) {