The New York-based infrastructure fund will pay 19 euros a share for the stake, the companies said, above Monday's closing price of 18.51 euros.
Criteria, the industrial holding company that owns Spanish lender Caixabank, and oil group Repsol will sell 10% each while retaining stakes of 24% and 20% respectively.
Repsol, which is under scrutiny from ratings agencies over its 11.7 billion euros of debt at a time of weak oil prices, said it stands to make a 246 million euro capital gain from the deal.
Criteria
