diff --git a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
index 32e2bf106f..e64757763d 100644
--- a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
+++ b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
@@ -858,9 +858,18 @@ export abstract class PortfolioCalculator {
     unitPriceAtEndDate: Big;
     unitPriceAtStartDate: Big;
   }): PortfolioOrderItem[] {
+    if (orders.length <= 0) {
+      return [];
+    }
+
     const assetProfileIdentifier = getAssetProfileIdentifier(assetProfile);
     const dateStringOfFirstActivity = orders[0].date;
-    const ordersWithMarketPrices = [...orders];
+
+    // Copy the items as they are enriched below. A shallow copy is sufficient
+    // because only top-level properties are written.
+    const ordersWithMarketPrices = orders.map((order) => {
+      return { ...order };
+    });
 
     // Add a synthetic order at the start and the end date
     ordersWithMarketPrices.push({
diff --git a/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator.ts b/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator.ts
index 6f73f6990d..873bffd4a8 100644
--- a/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator.ts
+++ b/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator.ts
@@ -183,13 +183,8 @@ export class RoaiPortfolioCalculator extends PortfolioCalculator {
       symbol
     });
 
-    // Copy the items as they are enriched below. A shallow copy is sufficient
-    // because only top-level properties are written.
-    let orders: PortfolioOrderItem[] = (
-      this.activitiesByAssetProfileIdentifier[assetProfileIdentifier] ?? []
-    ).map((activity) => {
-      return { ...activity };
-    });
+    let orders: PortfolioOrderItem[] =
+      this.activitiesByAssetProfileIdentifier[assetProfileIdentifier] ?? [];
 
     const isCash = orders[0]?.assetProfile?.assetSubClass === 'CASH';