About six months before Credit Suisse was sold to rival UBS in a weekend rescue, the head of the Swiss central bank wanted to inject 50 billion Swiss francs ($57.6 billion) into the lender and nationalise it, according to three sources with direct knowledge of the matter.

A parliamentary investigation into the collapse of Credit Suisse will keep its files closed for 50 years, according to a parliamentary committee document, a level of secrecy that has triggered concern among Swiss historians.

A group of Credit Suisse AT1 bondholders has filed a class action suit accusing former executives at the Swiss bank, including three past chief CEOs, of being responsible for the bank's downfall.

Financial markets have been thrown a fresh curve ball by the decision to write down 16 billion Swiss francs ($17.5 billion) of Credit Suisse bonds, known as Additional Tier 1 or AT1 debt, to zero as part of a forced rescue merger with UBS (UBSG.S).

Days before a hastily convened press conference late on Sunday that would make the world's front pages, Switzerland's political elite were secretly preparing a move that would jolt the globe.

Banking stocks tumbled on Monday as initial relief over a historic state-backed rescue of troubled lender Credit Suisse by Swiss rival UBS Group gave way to new worries about the risks of high-yield debt issued by big banks.

UBS Group (UBSG.S) emerged as Switzerland’s one and only global bank with a state-backed rescue of its smaller peer Credit Suisse, a risky bet that makes the Swiss economy more dependent on a single lender.

Banking giant UBS (UBSG.S) is in discussions to take over all or parts of Credit Suisse (CSGN.S), with the boards of Switzerland's two biggest lenders set to meet separately over the weekend, the Financial Times reported on Friday.

Credit Suisse (CSGN.S) said on Thursday it would borrow up to $54 billion from Switzerland's central bank to shore up liquidity and investor confidence, after a slump in its shares had intensified fears about a global banking crisis.