The coming-of-age drama will screen in the Cannes market today.
IFC plans to release Mermaid through its new Festival Direct offering, part of IFC Entertainment's multi-platform distribution model.
'Part of the reason we created Festival Direct was to give great films like Mermaid the opportunity to be seen by a wide audience,' said Jonathan Sehring, president of IFC Entertainment.
'We were dazzled by Mermaid when we saw it at Sundance. It does what all great fairy tales do; it transports us to another world. Anna is a truly gifted film-maker that we are thrilled to have opportunity to work with.'
The story follows an introverted girl who thinks she can make her wishes come true; her beliefs are challenged when she goes to Moscow as a young woman.
Arianna Bocco, vice president of acquisitions and production for IFC Films, negotiated the acquisition with Mark Ankner from Endeavor and Armen Dishdishyan from Central Partnership on behalf of the film-makers.