Nippon Steel and U.S. Steel said Wednesday they have finalized their “historic partnership,” a deal that gives the U.S. government a say in some matters and comes a year-and-a-half after the Japanese company first proposed its nearly $15 billion buyout of the iconic American steelmaker.

Japan-based Nippon Steel on Wednesday completed its buyout of U.S. Steel, changing its name to Nippon Steel North America, as the former U.S. industrial giant ended trading on Wall Street under its former brand name.

The deal gives the White House extraordinary control over U.S. Steel as part of a pact to alleviate national security concerns.