diff --git a/MarketDataService/src/main/java/com/joe/trading/marketdataservice/model/MarketData.java b/MarketDataService/src/main/java/com/joe/trading/marketdataservice/model/MarketData.java
index 259d259..f0a0828 100755
--- a/MarketDataService/src/main/java/com/joe/trading/marketdataservice/model/MarketData.java
+++ b/MarketDataService/src/main/java/com/joe/trading/marketdataservice/model/MarketData.java
@@ -34,6 +34,10 @@ public class MarketData implements Serializable {
 
     private String EXCHANGE;
 
+    public MarketData(String ticker){
+        this.TICKER = ticker;
+    }
+
     @Override
     public String toString() {
         return "MarketData{" +
diff --git a/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/MarketDataServiceTest.java b/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/MarketDataServiceTest.java
index cd3dd6a..028d2e9 100755
--- a/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/MarketDataServiceTest.java
+++ b/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/MarketDataServiceTest.java
@@ -154,7 +154,7 @@ void testInitialSubscriptionCheck(){
 
     @Test
     void buildInitialCacheEntryTest() throws JsonProcessingException {
-        List<MarketData> marketDataList = Arrays.asList(new MarketData(), new MarketData());
+        List<MarketData> marketDataList = Arrays.asList(new MarketData("IBM"), new MarketData("AAPL"));
         Object[] marketDataArray = marketDataList.toArray();
 
         when(restTemplate.getForEntity(anyString(), eq(Object[].class)))
diff --git a/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/orderbook/OrderBookServiceTest.java b/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/orderbook/OrderBookServiceTest.java
index 74ae9b1..de9381f 100755
--- a/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/orderbook/OrderBookServiceTest.java
+++ b/MarketDataService/src/test/java/com/joe/trading/marketdataservice/services/orderbook/OrderBookServiceTest.java
@@ -37,11 +37,11 @@ public void setUp(){
     void testPublishOrderBook() throws JsonProcessingException {
         doNothing().when(natsService).publish(any(), any());
 
-        List<OrderBook> orderBooks = new ArrayList<>();
-        orderBooks.add(new OrderBook());
-        orderBooks.add(new OrderBook());
+        List<com.joe.trading.shared.dtos.OrderBook> orderBooks = new ArrayList<>();
+        orderBooks.add(new com.joe.trading.shared.dtos.OrderBook());
+        orderBooks.add(new com.joe.trading.shared.dtos.OrderBook());
 
-        OrderBook[] orderBookArray = new OrderBook[orderBooks.size()];
+        com.joe.trading.shared.dtos.OrderBook[] orderBookArray = new com.joe.trading.shared.dtos.OrderBook[orderBooks.size()];
         int count = 0;
 
         while (count < orderBooks.size()){
@@ -49,12 +49,12 @@ void testPublishOrderBook() throws JsonProcessingException {
             count += 1;;
         }
 
-        when(restTemplate.getForEntity(anyString(), eq(OrderBook[].class)))
+        when(restTemplate.getForEntity(anyString(), eq(com.joe.trading.shared.dtos.OrderBook[].class)))
                 .thenReturn(ResponseEntity.ok(orderBookArray));
 
         orderBookService.publishOrderBook();
 
-        verify(natsService, times(8)).publish(any(), any());
+        verify(natsService, times(32)).publish(any(), any());
 
     }
 }
diff --git a/OrderProcessingService/src/main/java/com/joe/trading/order_processing/nats/NatsSubscriber.java b/OrderProcessingService/src/main/java/com/joe/trading/order_processing/nats/NatsSubscriber.java
index 8b4ce67..25373f4 100755
--- a/OrderProcessingService/src/main/java/com/joe/trading/order_processing/nats/NatsSubscriber.java
+++ b/OrderProcessingService/src/main/java/com/joe/trading/order_processing/nats/NatsSubscriber.java
@@ -137,6 +137,10 @@ private List<OrderBook> updateInternalOrders(String cacheKey, String key, List<c
          List<OrderBook> orderBooksForKey = books.stream()
                  .map(orderBookMapper::mapToOrderBook).toList();
 
+         if (openOrders == null){
+             return orderBooksForKey;
+         }
+
          orderBooksForKey.forEach(book -> {
              if (openOrders.contains(book.getId())){
                  internalOrders.add(book);