Wall Street rallies to its best day in months, but that’s not enough to salvage its losing week

NEW YORK — U.S. stocks rallied to their best day in months on Friday as Wall Street’s roller coaster suddenly shot back upward. That still wasn’t enough to keep the U.S. market from a fourth straight losing week, its longest such streak since August. The S&P 500 jumped 2.1% a day after closing…