Barclays Bank is to lend its support to England's new academies and free schools.
The bank will offer £1m to groups that want to set up free schools and invest £15m in money management courses.
It will also offer work experience to 3,000 pupils aged 16 to 18 from academies and free schools, and encourage staff to become governors.
The National Union of Teachers accused the government of "opening up schools to the market place".
A total of 24 free schools opened in September last year and 71 are due to open from this September.
Academies and free schools are key parts of changes the coalition government has brought in.
They are state-funded but with more freedom over the curriculum and teachers' pay and conditions than other schools.
The government wants all schools to become academies, which stand aside from local authority control.
Free schools can be set up by groups including charities, businesses, parents and religious bodies.
But critics opposed to free schools and the expansion of academies say this will lead to a two-tier system and the break-up of the state education system.
Barclays plans to expand money management courses already running in some schools over three years at a cost of £15m.
It will also offer free banking to new free schools and academies, to help get them off the ground.
Groups wanting to set up free schools could also be eligible for an average of £5,000 in grants out of a £1.25m fund to help pay for research and planning, Barclays says.
The chief executive of Barclays retail and business banking, Antony Jenkins, said: "It's a sizeable commitment.
"Barclays is supporting free schools and academies because we want to boost financial skills for young people."
He added: "We really do believe in the power of education to create social mobility, to create powerful effects in people's lives and to create economic growth, which of course is important to us as a bank."
Mr Jenkins said it was important to give children real work experience, not just "tidying up the photocopying room and making coffee for people" and those coming to Barclays would get that - and experience what it was like in the world of work.
Education Secretary Michael Gove announced the link-up at an academy in central London, saying it would help underprivileged children because free schools were mainly being set up in poorer communities.
"I'm delighted that Barclays have read the new educational landscape so clearly and decided to make a real difference," he said.
"Thanks to this commitment and generous package, students, teachers and governors will benefit enormously."
Describing Barclays as one of "Britain's most impressive and responsible companies", Mr Gove said it would be the "leader of the pack" but he expected other companies to be "pitching in to help in the fantastic work being done in state education".
NUT general secretary Christine Blower said: "Children and young people should not be influenced at an impressionable age by whichever large company manages to gain a foothold in their school.
"This is, of course, Michael Gove's vision for the future of education in this country. It is extraordinarily flawed and will most certainly result in a two-tier system.
"Any successful business's involvement in a school will surely be decided on what returns they can reap for themselves.
"While becoming a golden goose for big business, Michael Gove's academies and free schools policy is utterly undermining the principle of a fair education for all".
Asked if Barclays was concerned about supporting the academies and free schools programmes when they had attracted strong criticism from teaching unions and others, Mr Jenkins said: "Barclays is a non-political organisation.
"We are happy to support this initiative - we think it is going to have a lot of impact - but it is not the only thing we are doing in the educational space by any means."