NEW YORK — Wall Street snapped out of its stupor and posted its best performance of the year yesterday, finding a badly needed glimmer of optimism in the most unlikely of places: Citigroup is actually managing to turn a profit.

The 379-point gain for the Dow Jones industrials, a rally of almost 6 percent, was a welcome break from almost uninterrupted selling. A gain today would give the Dow its first two-day winning streak since early February. But Wall Street is used to false starts. The Dow had gained 200 points in a single day five times in 2009 before Tuesday. Each time, it lost ground in the next session, twice by triple digits.