(Reuters) -The S&P 500 sold off sharply on Tuesday to close below 5,000 points for the first time in almost a year after it reversed a strong morning rally, while investor hopes faded for any imminent U.S. delays or concessions on tariffs ahead of a midnight deadline. The S&P 500 has lost $5.83 trillion in market value, for its steepest four days of losses since the index was created in the 1950s, following President Donald Trump unveiling of hefty global tariffs against U.S. trading partners late on Wednesday. The S&P had risen more than 4% earlier on Tuesday as investors hoped that Trump would soften his stance or postpone a Wednesday deadline for tariffs.