Spanish utility Iberdrola has agreed to acquire the 18.4% of Avangrid it does not already own, the U.S. subsidiary said Friday, in an all-cash deal worth about $2.6 billion.

The deal comes after Avangrid in January abandoned an $8.3 billion deal to acquire U.S. competitor PNM Resources when it failed to win approval from New Mexico's utility regulator, more than three years after first announcing the plan.

Iberdrola will pay $35.75 per share for Avangrid's outstanding shares, and the deal is expected to close in the fourth quarter, Avangrid said in its statement.

Avangrid operates renewable energy assets in 24 states, and also serves 3.3 million customers in New York and New England through regulated utility operations, according to its website.

($1 = 0.9199 euros)

(Reporting by David French in New York; Spanish edition by Javier López de Lérida)