It has to sometime--why not yesterday?
The chatter on Bloomberg is the most optimistic I've heard in a long while. And Vikram Pandit sounds positively giddy with the news that Citigroup was profitable in January and February; his stock is up more than 40% on the news, which would be more impressive if that didn't represent a gain of less than 50 cents per share.
But as traders say, even a dead cat will bounce if you drop it from high enough. I'd put my money on short covering before I'd bet on a bottom.