The biggest bank according to market cap is now Bank of America, which recently topped Citigroup on an end-of-day basis. It had already achieved that milestone on an intraday basis. This is one of lighter sort of news stories that can come off as bad news. For Citigroup, the "news" basically serves as a reminder to all that its stock has not fared well under Chuck Prince, even as Bank of America has thrived--but it's not the kind of thing that shareholders are going to make an issue of. And the market cap-big could easily switch, one good or bad day is all it takes. Citigroup remains the biggest bank by assets, $1.63 trillion to Bank of America's $1.45 trillion.  

For more:
- Here's an update from the AP
- One of the secrets of BofA's success. Article
- Chuck Prince's era of troubles. Article