diff --git a/src/main/java/edu/ntnu/idi/idatt2003/g40/mappe/Portfolio.java b/src/main/java/edu/ntnu/idi/idatt2003/g40/mappe/Portfolio.java
index e69de29..f27e44c 100644
--- a/src/main/java/edu/ntnu/idi/idatt2003/g40/mappe/Portfolio.java
+++ b/src/main/java/edu/ntnu/idi/idatt2003/g40/mappe/Portfolio.java
@@ -0,0 +1,79 @@
+package edu.ntnu.idi.idatt2003.g40.mappe;
+
+import java.util.ArrayList;
+import java.util.List;
+import java.util.Objects;
+
+/**
+ * Represents a player's portfolio of shares.
+ * <p>
+ * The portfolio stores shares and provides operations for adding, removing,
+ * retrieving and checking ownership of shares.
+ * </p>
+ */
+public class Portfolio {
+
+    private final List<Share> shares = new ArrayList<>();
+
+    /**
+     * Creates an empty portfolio.
+     */
+    public Portfolio() {
+        // Intentionally empty
+    }
+
+    /**
+     * Adds a share to the portfolio.
+     *
+     * @param share the share to add
+     * @return {@code true} if the share was added, {@code false} otherwise
+     */
+    public boolean addShare(Share share) {
+        Objects.requireNonNull(share, "share cannot be null");
+        return shares.add(share);
+    }
+
+    /**
+     * Removes a share from the portfolio.
+     *
+     * @param share the share to remove
+     * @return {@code true} if the share was removed, {@code false} if it was not present
+     */
+    public boolean removeShare(Share share) {
+        Objects.requireNonNull(share, "share cannot be null");
+        return shares.remove(share);
+    }
+
+    /**
+     * Returns an immutable snapshot of all shares in the portfolio.
+     *
+     * @return a list of shares
+     */
+    public List<Share> getShares() {
+        return List.copyOf(shares);
+    }
+
+    /**
+     * Returns an immutable snapshot of all shares whose stock symbol matches the given symbol.
+     *
+     * @param symbol the stock symbol to match
+     * @return a list of shares matching the symbol
+     */
+    public List<Share> getShares(String symbol) {
+        Objects.requireNonNull(symbol, "symbol cannot be null");
+        return shares.stream()
+                .filter(s -> symbol.equalsIgnoreCase(s.getStock().getSymbol()))
+                .toList();
+    }
+
+    /**
+     * Checks whether the given share exists in the portfolio.
+     *
+     * @param share the share to check
+     * @return {@code true} if the portfolio contains the share, otherwise {@code false}
+     */
+    public boolean contains(Share share) {
+        Objects.requireNonNull(share, "share cannot be null");
+        return shares.contains(share);
+    }
+}