With gains of just 7% so far this year, Broadcom (AVGO +1.90%) stock has been underperforming the broader semiconductor sector in 2026. The PHLX Semiconductor Sector, for comparison, has jumped 58% this year. The stock’s expensive valuation explains Broadcom’s underperformance. After all, it is trading at 62 times trailing earnings. Of course, Broadcom delivered an…