The foundation set up by Microsoft founder Bill Gates will continue to support projects that would not otherwise be funded, even if they might fail.
In his annual letter outlining the work of the Bill & Melinda Gates Foundation and looking at areas for future investment, Gates says his foundation aims to "take a long-term view and take large risks on new approaches".
The letter says the foundation is focusing on funding education, food and health programmes. It says it does not have a role in funding sustainable energy because it prefers to invest in areas where there is not already a big market.
"We have a framework for deciding which innovations we get behind," it says. "A key criterion for us is that once the innovation is proven, the cost of maintaining it needs to be much lower than the benefit, so that individuals or governments will want to keep it going when we are no longer involved."
The letter says many applications for funding were unsuccessful because they did not demonstrate that this need would be met.
It says the foundation also considers "the ability to find partners with excellent teams of people who will benefit from significant resources over a period of five to 15 years" when deciding how to allocate its funds.
The foundation awards most of its grants to US organisations. Its funding priorities are improving health and reducing extreme poverty in the developing world, and it awards grants to charities that tackle emergency relief, urban poverty, agricultural development and water, sanitation and hygiene.
The foundation's London office is due to open early this year.