(Bloomberg) U.S. stocks rallied, sparing the Standard & Poor’s 500 Index from its worst January ever, after the world’s largest bond insurer said it expects to keep its AAA credit rating.

The S&P 500 added 22.69 points, or 1.7 percent, to 1,378.5, reversing an earlier 1.6 percent drop spurred by a steeper-than- forecast increase in jobless claims. The Dow gained 1.7 percent to 12,650.36. The Nasdaq Composite Index climbed 40.86, or 1.7 percent, to 2,389.86. Four stocks rose for every one that fell on the New York Stock Exchange. [More]