Tom Hayes launches a legal claim against UBS, claiming he was the bank's "hand-picked scapegoat".
The companies include UK multinationals such as HSBC, Prudential, and Legal & General.
The Swiss firm reports the biggest-ever quarterly return for a bank after buying Credit Suisse.
The Swiss lender is the 18th firm to reach a settlement with US prosecutors investigating the 2008 crisis.
Investors are suing the Swiss government over its handling of the takeover of Credit Suisse.
The failed Swiss lender faced shareholders for the first time since a forced rescue by rival UBS.
The rushed takeover deal is to be investigated by Switzerland's federal prosecutor.
Worries over the financial strength of the sector persist, with Deutsche Bank down 14% at one point.
Despite the swift action by regulators, stock markets in the UK and Asia fell.
