US stock futures wavered as investors digested another difficult day for tech stocks and persistent uncertainty on Federal Reserve policy.

A steep slide in shares of semiconductor companies was dragging on the Nasdaq Composite on Tuesday afternoon, putting the tech-heavy index on track for a rare underperformance versus the Dow Jones Industrial Average.

U.S. stocks finished mixed on Tuesday as a sell-off in tech stocks weighed on the broader market. The S&P 500 (SNPINDEX: ^GSPC) fell 37.78 points, or 0.6%, to 6,411.37, while the Nasdaq Composite (NASDAQINDEX: ^IXIC) tumbled 314.82 points, or 1.5%, to 21,314.95.