From c5198c2678d06f9c3f77fda9ce244a604ca00a6d Mon Sep 17 00:00:00 2001
From: Thomas Kaul <4159106+dtslvr@users.noreply.github.com>
Date: Fri, 2 Oct 2026 21:06:26 +0200
Subject: [PATCH] Carry forward of market prices between chart dates

---
 .../app/portfolio/calculator/portfolio-calculator.ts   |  9 ++-------
 ...l-buy-with-market-price-between-chart-dates.spec.ts | 10 ++++++----
 .../api/src/app/portfolio/current-rate.service.mock.ts |  4 +++-
 3 files changed, 11 insertions(+), 12 deletions(-)

diff --git a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
index 8dfe6bccbb..eb1e6f9fac 100644
--- a/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
+++ b/apps/api/src/app/portfolio/calculator/portfolio-calculator.ts
@@ -810,7 +810,7 @@ export abstract class PortfolioCalculator {
 
       while (
         indexOfMarketPriceDate < marketPriceDates.length &&
-        marketPriceDates[indexOfMarketPriceDate] < dateString
+        marketPriceDates[indexOfMarketPriceDate] <= dateString
       ) {
         lastMarketPrice =
           marketSymbolMap[marketPriceDates[indexOfMarketPriceDate]][
@@ -830,13 +830,8 @@ export abstract class PortfolioCalculator {
         }
       }
 
-      const marketPrice = marketSymbolMap[dateString]?.[assetProfileIdentifier];
-
       const unitPrice =
-        marketPrice ??
-        lastMarketPrice ??
-        lastActivityUnitPrice ??
-        unitPriceAtEndDate;
+        lastMarketPrice ?? lastActivityUnitPrice ?? unitPriceAtEndDate;
 
       if (activitiesOfDate?.length > 0) {
         for (const activity of activitiesOfDate) {
diff --git a/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator-manual-buy-with-market-price-between-chart-dates.spec.ts b/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator-manual-buy-with-market-price-between-chart-dates.spec.ts
index e1fafe3810..989409e77b 100644
--- a/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator-manual-buy-with-market-price-between-chart-dates.spec.ts
+++ b/apps/api/src/app/portfolio/calculator/roai/portfolio-calculator-manual-buy-with-market-price-between-chart-dates.spec.ts
@@ -120,13 +120,14 @@ describe('PortfolioCalculator', () => {
       );
 
       /**
-       * The only historical market price is on 2023-06-15, which is not a
-       * chart date (every third day from 2021-01-03)
+       * The only historical market prices are on 2023-06-14 and 2023-06-15,
+       * which are not chart dates (every third day from 2021-01-03)
        */
+      expect(historicalDataByDate['2023-06-14']).toBeUndefined();
       expect(historicalDataByDate['2023-06-15']).toBeUndefined();
 
       /**
-       * The chart dates before the market price use the unit price of the
+       * The chart dates before the market prices use the unit price of the
        * activity: 50
        */
       expect(historicalDataByDate['2023-06-13']).toMatchObject({
@@ -136,7 +137,8 @@ describe('PortfolioCalculator', () => {
       });
 
       /**
-       * The chart dates after the market price carry it forward: 100
+       * The chart dates after the market prices carry the latest one forward
+       * (100), not the first one (80)
        */
       expect(historicalDataByDate['2023-06-16']).toMatchObject({
         netPerformance: 500, // 10 * (100 - 50) = 500
diff --git a/apps/api/src/app/portfolio/current-rate.service.mock.ts b/apps/api/src/app/portfolio/current-rate.service.mock.ts
index 869e0de974..18739ddab5 100644
--- a/apps/api/src/app/portfolio/current-rate.service.mock.ts
+++ b/apps/api/src/app/portfolio/current-rate.service.mock.ts
@@ -33,7 +33,9 @@ function mockGetValue({
     case '6c0c5cee-0208-4975-b473-03baf2518497':
       // Sparse market data with the quote of today, which falls back to the
       // latest market price
-      if (
+      if (isSameDay(parseDate('2023-06-14'), date)) {
+        return { marketPrice: 80 };
+      } else if (
         isSameDay(parseDate('2023-06-15'), date) ||
         isSameDay(parseDate('2024-01-31'), date)
       ) {