Social Investment Business received more than 3,000 applications for investments totalling more than £500m in the past 12 months, according to its first impact report, Investing in the Future.
Jonathan Lewis, chief executive of Social Investment Business, said the high demand for funding had proved there was a need for more social investment in the voluntary sector.
"We want to build on our success by attracting more money into the sector, so that we can help more organisations do more of what they do best – help individuals and communities most in need," he said.
Social Investment Business, which is a social enterprise, manages 440 investments worth between £3,000 and £5.9m.
At a parliamentary reception held by the organisation last week, Stephen Bubb, its chair, said demand for funding from Futurebuilders, which issues loans and grants to help voluntary organisations win public service contracts, was running at £60m to £90m a month when it closed for applications in January.
He said this level of demand would exhaust the Government's proposed £75m social investment wholesale bank in just one month.