Mr Green, speaking at the Hay Festival on the Welsh borders on Saturday, said it would be of particular relevance to those who would grow up to become part of the sub-prime market.
"Part of the answer lies in financial literacy education in schools," said Mr Green, promoting his 2009 book Good Value: Reflections on Money, Morality and an Uncertain World.
"I really don't think it's wise in the circumstances of modern life to have people come out of the school system into working life or, sadly, often not working life, without the very basics of financial literacy."
Mr Green, who has been chairman of HSBC since 2005, and is also an ordained priest, was keen to stress that there was a social imperative for banking services to be open to those on lower incomes.
However, he said some forms of lending were unacceptable, citing 110pc mortgages, and said those at the bottom end of the market may not have had proper understanding or access to information when taking out such loans.
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