Balfour Beatty’s Regional & City Airports consortium paid £60m when it bought the airport from Devon County Council in 2007.
The remaining 40% isowned by Galaxy Sarl, a specialist fund backed by French and Italian investors and the European Commission.
The sale price this time was not disclosed but Balfour Beatty said that the proceeds from the sale would be used to repay the funders.
Last year the value of the investment was written down from £12m to zero in the company’s accounts.
Balfour Beatty chief executive Andrew McNaughton said: "We are pleased to have come to an arrangement with our JV partner and the funders that ensures the future viability of the airport for its staff and the local community it serves.”
Rigby Group also owns Coventry Airport.