The Standard & Poor’s 500 Index fluctuated amid mixed corporate earnings results, and as a plunge in Valeant Pharmaceuticals International Inc. sparked a second day of selling in biotechnology shares.

Valeant dropped 27 percent after a critical research report. General Motors Co. climbed 6.3 percent after posting a better-than-estimated profit. Chipotle Mexican Grill Inc. and EMC Corp lost more than 5 percent after their profits were short of estimates. KLA-Tencor Corp. jumped 23 percent after Lam Research Corp. agreed to acquire the company for $10.6 billion, while SanDisk Corp. added 2.7 percent after its deal to be bought by Western Digital Corp.

The S&P 500 gained 0.2 percent to 2,033.93 at 12:27 p.m. in New York, after rising as much as 0.4 percent. The Dow Jones Industrial Average added 77.53 points, or 0.5 percent, to 17,294.64, as Travelers Cos. and United Technologies Corp. rallied for a second day, joined by Boeing Co. after it raised its profit forecast. The Nasdaq Composite Index was little changed as biotechnology shares retreated for a second day.

The S&P 500 is making little progress for a third session after reaching a two-month high. Equities have been recovering from a summer selloff and the benchmark’s first correction in four years, which was fed by anxiety over China’s slowdown and confusion on the Federal Reserve’s intentions toward interest rates. The S&P 500 is up 5.9 percent this month, rebounding from its worst quarter since 2011.

Investors are looking to corporate America for clues on the strength of the economy as the Federal Reserve considers raising interest rates for the first time in almost a decade. The probability of a Fed rate increase this year is about 34 percent, according to data compiled by Bloomberg. March is the first month for which traders price in at least even odds of a boost.

Source: Bloomberg.