The bank said the fund, known as the Triodos Opportunities Fund, had been set up to make equity investments in growing social enterprises, but that there were not enough businesses that met its criteria.
"We were looking for mature, scaleable businesses in the UK that were looking for equity to grow," said Charles Middleton, managing director of Triodos in the UK.
"We didn’t find a pipeline of businesses like that to lend to. We looked at a number of propositions and found that they didn’t meet our requirements."
He said Triodos would continue to lend to the charity and social enterprise sectors, and would consider launching another fund to take equity in the social enterprise market "when the time is right".