diff --git a/index.js b/index.js
index 7615706..fb5a167 100644
--- a/index.js
+++ b/index.js
@@ -562,11 +562,11 @@ Kraken.prototype._listTransactionsRecursive = function (type, start, knownTransa
           const msg = err.cause ? err.cause.message : err.message;
           if(msg.match(new RegExp('Invalid currency \'[A-Z]{2,4}\'', 'g'))){
             this.logger.info(err, msg);
-            return null; //convertFromKrakenTransaction can also return null so we just continue with that as "invalid"
+            return null;
           }
           throw err;
         }
-      });
+      }).filter(item => item !== null);
 
       // Merge our newly converted transactions with the ones from previous calls
       const allTransactions = transactions.concat(knownTransactions);
diff --git a/package-lock.json b/package-lock.json
index 8bc17f3..5141420 100644
--- a/package-lock.json
+++ b/package-lock.json
@@ -1,6 +1,6 @@
 {
   "name": "kraken-exc",
-  "version": "2.5.4",
+  "version": "2.5.5",
   "lockfileVersion": 1,
   "requires": true,
   "dependencies": {
diff --git a/package.json b/package.json
index def0349..eae0036 100644
--- a/package.json
+++ b/package.json
@@ -43,5 +43,5 @@
     "test": "LOG_LEVEL=fatal mocha --config .mocharc.json",
     "test-watch": "LOG_LEVEL=info mocha --config .mocharc.json --watch"
   },
-  "version": "2.5.4"
+  "version": "2.5.5"
 }
diff --git a/test/unit/listTransactions.test.js b/test/unit/listTransactions.test.js
index 51d4843..b8a90f5 100644
--- a/test/unit/listTransactions.test.js
+++ b/test/unit/listTransactions.test.js
@@ -380,7 +380,7 @@ describe('listTransactions', () => {
         currency: 'BTC',
         type: 'deposit',
         raw: depositRawObject
-      }, null //this is the invalid currency
+      }
     ];
 
     const withdrawalReqStub = reqStub.withArgs(sinon.match.any, 'Ledgers', sinon.match({ type: 'withdrawal' }));