diff --git a/web/src/components/ComparisonChart.tsx b/web/src/components/ComparisonChart.tsx
index c888fc6e..f2077e93 100644
--- a/web/src/components/ComparisonChart.tsx
+++ b/web/src/components/ComparisonChart.tsx
@@ -38,7 +38,19 @@ export function ComparisonChart({ traders }: ComparisonChartProps) {
       const traderIds = traders.map((trader) => trader.trader_id)
       const batchData = await api.getEquityHistoryBatch(traderIds)
       return traders.map((trader) => {
-        return batchData.histories[trader.trader_id] || []
+        const history = batchData.histories?.[trader.trader_id] || []
+
+        // If backend doesn't return total_pnl_pct, calculate it from equity
+        if (history.length > 0 && history[0].total_pnl_pct === undefined) {
+          const initialEquity = history[0].total_equity
+          history.forEach((point: any) => {
+            point.total_pnl_pct = initialEquity > 0
+              ? ((point.total_equity - initialEquity) / initialEquity) * 100
+              : 0
+          })
+        }
+
+        return history
       })
     },
     {