Financial Winners & Losers: Citigroup

CHARLOTTE, N.C. -- Shares of national banks plunged Friday amid worries about the economy and concerns that the government's financial rescue plan won't be sufficient to cover future losses.

Leading the way was Citigroup (C Quote), which is scheduled to hold a board meeting Friday to discuss whether to sell all or part of itself, The Wall Street Journal reported. Citigroup's shares tumbled more than 20% to below $4 a share -- their lowest level in more than 15 years.

Concerns are growing that the deteriorating economy and still-turbulent markets will slam banks with more write-downs in the coming quarters. What began as a subprime residential mortgage crisis has ballooned into a full-blown debt crisis, escalating defaults in everything from leveraged loans to credit card debt to commercial real estate loans. ...