US stocks finished lower Wednesday as a morning rally fizzled and Apple shares dropped after unveiling a suite of upgraded smartphone, tablet and television products.

At the closing bell, the Dow Jones Industrial Average was at 16,256.01, down 236.67 points (1.44 percent).

The broad-based S&P 500 dropped 27.21 (1.38 percent) to 1,942.20, while the tech-rich Nasdaq Composite Index fell 55.40 (1.15 percent) to 4,756.53.

US stocks rose earlier in the day, following rallies in Asia and Europe, but turned negative at midday.

"The pattern of a see-saw market, one day up, one day down, is here for the time being and investors shift positions accordingly," said David Levy, portfolio manager at Kenjol Capital Management.

Apple, the market heavyweight, fell 1.9 percent after the tech giant launched new iPhones with pressure-sensing capacity, upgraded iPads and an improved Apple TV device.