Shares of Lehman Brothers plunged 13.6% on Wednesday, bringing their total loss in the past four days to more than 25%, on concerns about the potential for further write-downs and investors’ declining confidence in the investment bank’s management, reports Reuters. The stock’s latest drop followed the FT’s report that Lehman could seek extra capital from Korean institutions after raising $6bn on Monday, and a downgrade by a prominent analyst. Separately, Reuters reports that Washington Mutual on Wednesday denied what it called market rumours about regulatory activity after the shares fell more than 9% to a 16-year low.