Xiaomi is one of Apple‘s (NASDAQ: AAPL) biggest rivals in the Chinese smartphone market, but the six-year-old start-up has only taken baby steps into the U.S. market. It launched a U.S. shopping portal for headphones, power banks, fitness trackers, and other accessories last year. Earlier this year, it declared its intentions to enter the U.S. smartphone market despite tough competition and concerns about saturation.