Credit Suisse AG staff are planning to sue the Swiss financial regulator over the cancellation of $400 million in bonuses following the troubled lender's rescue by UBS Group AG, according to the Financial Times.

Senior managers at Credit Suisse have approached law firms Quinn Emanuel and Pallas to request legal action on their behalf. These law firms are already involved in suing Swiss regulator Finma on behalf of investors who owned AT1 bonds.

According to Reuters, both Credit Suisse and Finma declined to provide a comment on the matter. Law firms Quinn Emanuel and Pallas also did not respond. 

Litigators were alerted and the markets were stunned when the Swiss regulator, as part of the takeover in March, deemed approximately $18 billion of Credit Suisse's Additional Tier 1 (AT1) debt as worthless.

The agreement disrupted a well-established practice of prioritising bondholders over shareholders in terms of debt recovery, leading to the initiation of numerous lawsuits.