here will be a sense of deja vu on Wall Street with Buffett's Goldman deal: In 1987 he paid $700 million for a 12% stake in what was then Wall Street’s largest investment bank -- Salomon Inc., a firm as respected (and feared) in its day as Goldman is now.

But that investment wound up putting Buffett through the wringer, after the government in 1991 accused Salomon of trying to corner government securities markets. The charges threatened to destroy the firm.

Buffett stepped in as chairman of Salomon to save its reputation and get it back on track. The firm was later acquired by Travelers Group, the predecessor of Citigroup Inc.