diff --git a/src/main/java/nl/utwente/ing/controller/BalanceHistoryController.java b/src/main/java/nl/utwente/ing/controller/BalanceHistoryController.java
index d78d5c1..7f8ba86 100644
--- a/src/main/java/nl/utwente/ing/controller/BalanceHistoryController.java
+++ b/src/main/java/nl/utwente/ing/controller/BalanceHistoryController.java
@@ -147,7 +147,7 @@ public String getBalanceHistory(@RequestHeader(value = "X-session-ID", required
             List<HistoryItem> historyItems = new LinkedList<>();
 
             // Create an initial HistoryItem with the balance of the account as values.
-            HistoryItem currentItem = new HistoryItem(sum);
+            HistoryItem currentItem = new HistoryItem(sum, calendar.getTimeInMillis() / 1000);
             historyItems.add(currentItem);
 
             int groupCount = 0;
@@ -155,7 +155,8 @@ public String getBalanceHistory(@RequestHeader(value = "X-session-ID", required
             // In case there are no transactions, fill the results with groups representing the sum and no movement.
             if (transactionsSet.isAfterLast()) {
                 while (historyItems.size() < count) {
-                    historyItems.add(new HistoryItem(sum));
+                    calendar.add(intervalType, -1);
+                    historyItems.add(new HistoryItem(sum, calendar.getTimeInMillis() / 1000));
                 }
             }
 
@@ -165,9 +166,9 @@ public String getBalanceHistory(@RequestHeader(value = "X-session-ID", required
                 pointer.setTime(DATE_FORMAT.parse(transactionsSet.getString("date")));
 
                 while (calendar.after(pointer)) {
-                    currentItem = new HistoryItem(currentItem.getOpen());
-                    historyItems.add(currentItem);
                     calendar.add(intervalType, -1);
+                    currentItem = new HistoryItem(currentItem.getOpen(), calendar.getTimeInMillis() / 1000);
+                    historyItems.add(currentItem);
                 }
 
                 long amount = transactionsSet.getLong("amount");
@@ -186,9 +187,9 @@ public String getBalanceHistory(@RequestHeader(value = "X-session-ID", required
                     }
 
                     // Some data from the old group has to be carried over to the new group.
-                    currentItem = new HistoryItem(currentItem.getOpen());
-                    historyItems.add(currentItem);
                     calendar.add(intervalType, -1);
+                    currentItem = new HistoryItem(currentItem.getOpen(), calendar.getTimeInMillis() / 1000);
+                    historyItems.add(currentItem);
                 }
 
                 // Update the open value, which is the "current" value.
@@ -208,7 +209,8 @@ public String getBalanceHistory(@RequestHeader(value = "X-session-ID", required
             // In case not enough transactions were retrieved from the database to fill the count:
             // Similarly to the case of the empty set, create items of the last sum without any movement.
             while (historyItems.size() < count) {
-                historyItems.add(new HistoryItem(endSum));
+                calendar.add(intervalType, -1);
+                historyItems.add(new HistoryItem(endSum, calendar.getTimeInMillis() / 1000));
             }
 
             GsonBuilder gsonBuilder = new GsonBuilder();
@@ -238,6 +240,7 @@ public JsonElement serialize(HistoryItem historyItem, Type type, JsonSerializati
         object.addProperty("high", historyItem.getHigh() / 100.0);
         object.addProperty("low", historyItem.getLow() / 100.0);
         object.addProperty("volume", historyItem.getVolume() / 100.0);
+        object.addProperty("timestamp", historyItem.getTimestamp());
         return object;
     }
 }
diff --git a/src/main/java/nl/utwente/ing/model/HistoryItem.java b/src/main/java/nl/utwente/ing/model/HistoryItem.java
index d32e516..853d753 100644
--- a/src/main/java/nl/utwente/ing/model/HistoryItem.java
+++ b/src/main/java/nl/utwente/ing/model/HistoryItem.java
@@ -30,12 +30,14 @@ public class HistoryItem {
     private long high;
     private long low;
     private long volume;
+    private long timestamp;
 
-    public HistoryItem(long start) {
+    public HistoryItem(long start, long timestamp) {
         this.open = start;
         this.close = start;
         this.high = start;
         this.low = start;
+        this.timestamp = timestamp;
     }
 
     public long getOpen() {
@@ -73,4 +75,8 @@ public long getVolume() {
     public void setVolume(long volume) {
         this.volume = volume;
     }
+
+    public long getTimestamp() {
+        return timestamp;
+    }
 }