The Standard & Poor’s 500 Index capped its strongest two-day rally in three months, amid speculation central banks around the world will act to support the global economy even as the Federal Reserve tightens policy.

The S&P 500 gained 2 percent to 1,906.88 at 4 p.m. in New York, the best back-to-back increase since October after turning positive for the week.

Equities continued a snap-back from the worst start to a year since 2009, hammered as oil sank to 12-year lows amid rising supplies and concern that flagging global growth, particularly in China, will drag on the U.S. economy. Crude rallied Friday to its biggest two-day advance since 2009.

The S&P 500 rebounded yesterday from a 21-month low as European Central Bank President Mario Draghi signaled the potential for more stimulus as early as March. Sentiment also received a boost overnight from speculation that the Bank of Japan is considering additional easing.

The benchmark through Thursday was headed for a fourth weekly decline, and on Wednesday dipped below a level technical analysts call oversold, meaning a selloff has gone too far. A rout stoked by concerns about China’s slowdown and plunging oil wiped off as much as $2.45 trillion from U.S. equities this year.

Source : Bloomberg