diff --git a/src/main/java/Model/Transaction.java b/src/main/java/Model/Transaction.java
index 1ef6aa8..de68854 100644
--- a/src/main/java/Model/Transaction.java
+++ b/src/main/java/Model/Transaction.java
@@ -6,6 +6,16 @@ public abstract class Transaction {
     protected boolean committed;
 
     protected Transaction(Share share, int week, TransactionCalculator calculator) {
+        if (share == null) {
+            throw new IllegalArgumentException("Share cannot be null");
+        }
+        if (week < 1) {
+            throw new IllegalArgumentException("Week must be at least 1");
+        }
+        if (calculator == null) {
+            throw new IllegalArgumentException("Calculator cannot be null");
+        }
+
         this.share = share;
         this.week = week;
         this.calculator = calculator;