Stock Market News: Citigroup (NYSE:C), Sony (NYSE:SNE), Monsanto (NYSE:MON), Boeing (NYSE:BA), Argon ST (NASDAQ:STST)

A 17 percent plunge in Citigroup (NYSE:C) today triggered a five-minute trading pause, making the bank the second company halted by the two-week-old circuit- breaker program created to prevent market panics. The order that caused the slump, 8,820 shares of Citigroup that crossed for $3.3174 at 1:03:51 p.m. in New York, was canceled, according to data compiled by Bloomberg. The stock changed hands for $3.80 when trading resumed, compared with yesterday’s close of $4, as U.S. stocks posted the biggest losses in three weeks. –Bloomberg Sony (NYSE:SNE) announced that it is recalling 535,000 laptops that it sells under the Vaio brand. According to a number of media reports, the recall results from a temperature-control defect that could cause excessive heat and distort the laptop’s shape. The Wall Street Journal…