Two reasons, actually. 1.) Because, as I note in my piece this week, there's evidence that the banks--at least the four biggest ones--are semi-delusional about the size of the losses they still face. Historically, the banks themselves have been about the worst source you can find for an honest assessment of their own financial situation.
2.) Because, as the Times notes in its TARP repayment piece today, the race to return TARP money seems much more about seizing a competitive advantage and identifying oneself as a "healthy bank" than actually, you know, being a healthy bank. (Well, that an wriggling out of government-mandated pay restrictions.) From the Times: