UBS Group AG is mulling a takeover of its embattled Swiss rival Credit Suisse, other sources told Reuters on Saturday, amid a crisis of confidence in the bank that risks destabilizing the global financial system.

A spokesperson for the Treasury declined to comment. A spokesperson for the Bank of England's Prudential Regulation Authority, which oversees lenders, declined to comment.

The bank also has $44.6 billion of risk-weighted assets in its U.S. unit.