PITTSBURGH--(BUSINESS WIRE)--Alcoa Corporation (NYSE:AA) today made discretionary contributions to its U.S. pension plans of $500 million, the gross proceeds of a recently closed debt offering. On May 17, 2018, Alcoa Nederland Holding B.V., a wholly-owned subsidiary of Alcoa, closed its offering of $500 million aggregate principal amount of 6.125 percent senior notes due 2028. The notes were sold in a private placement to qualified institutional buyers in accordance with Rule 144A under the Sec.