Swiss prosecutor's takeover investigation causes UBS and Credit Suisse shares to plummet.

Shares of UBS and Credit Suisse fell after Switzerland's federal prosecutor opened an investigation into the emergency merger of the two lenders. The investigation is looking into potential breaches of the country's criminal law by government officials, regulators, and executives at the two banks. The UBS takeover of rival Credit Suisse was engineered by Swiss authorities in a bid to rein in turmoil in global banking.