Stocks back on upswing after 1-day stumble

The stock market reclaimed some losses from its biggest dive this year and returned Wednesday to its pattern of steady gains. Reassuring reports on productivity and hiring overshadowed worries about the Greek debt crisis.

Stock indexes made solid gains by midmorning after the government said oil refineries were operating at a faster clip than economists had expected. Oil refiners Valero Energy Corp. and Tesoro Inc. were among the biggest gainers in the Standard & Poor’s 500.

The Dow Jones industrial average closed up 78.18 points at 12,837.33.

The Dow dived 203 points Tuesday, the biggest hitch in a strong rally for stocks this year. Many market watchers believe that stocks had risen too quickly and were due for a setback. Before Tuesday, the Dow was up more than 6% in 2012.

“You wouldn’t expect to get it all back in one day,” said Jerry Webman of Oppenheimerfunds Inc.

The average has gained more than 20% since Oct. 3 and has proved resilient. Tuesday was the eighth time during that stretch that the Dow fell more than 200 points. Each previous time, it made up most or all losses within days.

Tuesday’s sell-off was triggered by fears that not enough private investors would exchange their Greek government bonds for replacements with a lower face value and interest rate.