On May 13, the semiconductor sector showed strong performance, indicating a deepening reliance of the broad market on this high-growth area. As of Monday, the weighting of 19 semiconductor and equipment stocks in the S&P 500 index has risen to 18%. According to O'Rourke, Chief Market Strategist at Jones Trading, semiconductor and memory stocks contributed to 70% of the $5.1 trillion increase in market capitalization added to the S&P 500 index by 2026. However, market observers have detected signs of weakness within the market. Data from Bespoke Investment Group reveals that despite the S&P 500 index reaching a record high earlier this week, just over half of the individual stocks were trading above their 50-day moving averages. O'Rourke cautions that the semiconductor sector's oversized weighting in the S&P 500 index poses a risk to the broad market, as any pullback or underperformance could have significant repercussions.