diff --git a/frontend/src/app/portfolio/[id]/benchmark/page.tsx b/frontend/src/app/portfolio/[id]/benchmark/page.tsx
index f1f87d5..d44d399 100644
--- a/frontend/src/app/portfolio/[id]/benchmark/page.tsx
+++ b/frontend/src/app/portfolio/[id]/benchmark/page.tsx
@@ -181,13 +181,13 @@ export default function BenchmarkPage() {
                         tickFormatter={(v: number) => `${v.toFixed(1)}%`}
                       />
                       <Tooltip
-                        formatter={(value: number | undefined, name: string) => {
+                        formatter={(value: number | undefined, name?: string) => {
                           const labels: Record<string, string> = {
                             portfolio_return: '포트폴리오',
                             benchmark_return: 'KOSPI',
                             deposit_return: '정기예금',
                           };
-                          return [`${value != null ? value.toFixed(2) : '-'}%`, labels[name] || name];
+                          return [`${value != null ? value.toFixed(2) : '-'}%`, labels[name || ''] || name || ''];
                         }}
                         labelFormatter={(label) => {
                           return new Date(String(label)).toLocaleDateString('ko-KR');
diff --git a/frontend/src/app/portfolio/[id]/drawdown/page.tsx b/frontend/src/app/portfolio/[id]/drawdown/page.tsx
index 10b8b76..6961e2a 100644
--- a/frontend/src/app/portfolio/[id]/drawdown/page.tsx
+++ b/frontend/src/app/portfolio/[id]/drawdown/page.tsx
@@ -265,7 +265,7 @@ export default function DrawdownPage() {
                         domain={['dataMin', 0]}
                       />
                       <Tooltip
-                        formatter={(value: number) => [`${value.toFixed(2)}%`, '낙폭']}
+                        formatter={(value?: number) => [`${value != null ? value.toFixed(2) : '-'}%`, '낙폭']}
                         labelFormatter={(label) => `날짜: ${label}`}
                       />
                       <ReferenceLine