diff --git a/libs/ui/src/lib/treemap-chart/treemap-chart.component.ts b/libs/ui/src/lib/treemap-chart/treemap-chart.component.ts
index 2876449a0d..f26d954528 100644
--- a/libs/ui/src/lib/treemap-chart/treemap-chart.component.ts
+++ b/libs/ui/src/lib/treemap-chart/treemap-chart.component.ts
@@ -156,7 +156,7 @@ export class GfTreemapChartComponent
   private getHolding(
     chart: Chart<'treemap'>,
     activeElement: ActiveElement
-  ): PortfolioPosition {
+  ): PortfolioPosition | undefined {
     if (!activeElement) {
       return undefined;
     }