Barclays Plc investors, blindsided by the bank's $451.4 millionregulatory fine for trying to rig benchmark rates, saw the stockdrop 16 percent a day later. Other bank shareholders may be just assurprised.

Barclays, like other lenders that help set key rates for $360trillion in securities, has given investors scant guidance on theliability they face for alleged market manipulation. More than adozen banks are being probed by U.S., Asian and European regulatorsfor collusion in setting interbank lending rates. The others havemirrored Barclays on minimal disclosure.

“The automatic reaction from investors is: 'Who's next?'” saidTodd Hagerman, a New York-based analyst at Sterne Agee & LeachInc. who recommends investors remain “cautious” on the biggest U.S.banks. “It's fair to assume that legal and related professionalfees and associated reserves are going to continue to remainelevated, if not increase.”