International Public Partnerships (INPP) has sold its minority stake in the Sheffield Building Schools for the Future (BSF) project for FTSE 250 peer HICL Infrastructure Company.The group said the disposal was being made on an opportunistic basis after HICL, which already owned a 40% stake, made the unsolicited offer for the 27-year project.HICL will acquire the 19% interest for £3.2m, which offers a premium of 8-9% internal rate of return to INPP, which said its "ability to transact at these levels provides a continuing indication of the demand for assets in the secondary market".INPP plans to re-invest the proceeds from the sale in its pipeline of new infrastructure opportunities that it is currently developing.HICL also announced that it has acquired a further 50% stake in the Oldham Library PFI project in partnership with its existing joint venture partner, Kajima Partnerships, which is a subsidiary of Kier.Under the deal, the joint venture owns a 90% stake in the 25-year project.HICL said the sums paid for both projects were in line with the current valuation of similar UK social infrastructure projects in its portfolio."We are pleased to have completed these two incremental acquisitions in good, operational projects which meet the group's strategy of increasing its stakes to majority ownership when the opportunity arises," the company said."It further demonstrates how the group can leverage the existing portfolio to increase ownership when suitable opportunities arise."