U.S. stock index futures continued to decline, with the Nasdaq 100 index futures falling more than 4%, the S & P 500 index futures falling more than 2%, and the Dow futures falling more than 1%. Semiconductor stocks continued to decline before the market, with NVIDIA (NVDA. O), TSMC (TSM. N) and Broadcom (AVGO. O) all falling more than 11%.