<br /> U.S. stock futures dropped by up to 1 percent on Tuesday as a technology rout in the previous session. Concerns over iPhone sales sapped investors’ appetite for high-growth companies. <br /><br />Shares of Apple Inc lost 1.4 percent in premarket trading, putting it on course for its seventh decline in the past nine sessions. That's around 20 percent down from a peak earlier this year that valued it at more than $1 trillion. <br />
