Which bank will trade under $1 next?

Now that Citigroup (C) has dropped below $1 in intraday trading, which bank could be next? That depends on whether financial stocks keep falling, but the number of analyst downgrades and first quarter write-offs could bring the sector down even further than it has already fallen.

Bank of America (BAC) could easily move below $1. Its 52-week low, which is near where the stock trades now, is $2.53. While the drop in Bank of America's stock is not as steep as Citi's over the last six months, it is close.