Plaid Cymru leader Leanne Wood called on the Financial Services Authority today to hand UBS's £160 million fine for rate-rigging to homeless charities and foodbanks.
Under previous rules it would have been offset against future fees but in the summer the government said fines should be returned to the taxpayer.
Ms Wood said the money should be used to help people who had lost out from the economic collapse brought on by financial firms.
She called the UBS fine "no more than a slap on the wrist.
"It was wrong for fines levied on banks to be paid back into the same pot at the Financial Services Authority as if banks were all just part of one big club with no responsibility to society.
"The punishment must fit the crime."
Ms Wood said the financial crisis and subsequent banker-pushed austerity measures had made many more people homeless.
"This money should be used to alleviate housing problems and support individuals and families who have fallen on hard times.
"With cuts to services being forced through by the UK government, this money could assist those services to help people who are often in desperate need of shelter and food, and have faced severe hardship because of the economic downturn."
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