diff --git a/lib/bcoin/fees.js b/lib/bcoin/fees.js
index e75aa44c..9e7de8b2 100644
--- a/lib/bcoin/fees.js
+++ b/lib/bcoin/fees.js
@@ -505,10 +505,12 @@ PolicyEstimator.prototype.isPriPoint = function isPriPoint(fee, priority) {
 PolicyEstimator.prototype.processTX = function processTX(entry, current) {
   var height = entry.height;
   var hash = entry.tx.hash('hex');
-  var fee, rate, priority;
+  var fee, rate, priority, stat;
 
   if (this.map[hash]) {
-    this.logger.debug('estimatefee: Mempool tx %s already tracked.', entry.tx.rhash);
+    this.logger.debug(
+      'estimatefee: Mempool tx %s already tracked.',
+      entry.tx.rhash);
     return;
   }
 
@@ -531,20 +533,22 @@ PolicyEstimator.prototype.processTX = function processTX(entry, current) {
   this.logger.spam('estimatefee: Processing mempool tx %s.', entry.tx.rhash);
 
   if (fee === 0 || this.isPriPoint(rate, priority)) {
-    this.map[hash] = {
-      blockHeight: height,
-      bucketIndex: this.priStats.addTX(height, priority)
-    };
-    this.mapSize++;
+    stat = new StatEntry();
+    stat.blockHeight = height;
+    stat.bucketIndex = this.priStats.addTX(height, priority);
   } else if (this.isFeePoint(rate, priority)) {
-    this.map[hash] = {
-      blockHeight: height,
-      bucketIndex: this.feeStats.addTX(height, rate)
-    };
-    this.mapSize++;
-  } else {
-    this.logger.spam('estimatefee: Not adding tx %s.', entry.tx.rhash);
+    stat = new StatEntry();
+    stat.blockHeight = height;
+    stat.bucketIndex = this.feeStats.addTX(height, rate);
   }
+
+  if (!stat) {
+    this.logger.spam('estimatefee: Not adding tx %s.', entry.tx.rhash);
+    return;
+  }
+
+  this.map[hash] = stat;
+  this.mapSize++;
 };
 
 /**
@@ -785,6 +789,16 @@ PolicyEstimator.fromRaw = function fromRaw(minRelay, data, logger) {
   return estimator;
 };
 
+/**
+ * StatEntry
+ * @private
+ */
+
+function StatEntry() {
+  this.blockHeight = -1;
+  this.bucketIndex = -1;
+}
+
 /**
  * DoubleMap
  * @private