A group of Credit Suisse investors have sued Swiss financial regulators after a government-engineered takeover of the struggling bank by rival UBS left them with billions in losses. The investors are contesting an order by the Swiss Financial Market Supervisory Authority, or FINMA, that wiped out about 16 billion Swiss francs ($17.3 billion) in higher-risk Credit Suisse bonds as part of an emergency rescue last month, lawyers said Friday.