Northrop Grumman Executive Resigns

Northrop Grumman Corp., the fourth-largest U.S. defense contractor, said Ralph Crosby resigned as head of its Integrated Systems business and will be replaced by executive Scott Seymour.

Crosby, 54, a 20-year veteran of the company, quit to “pursue other interests.� His resignation is effective at the end of the year, spokesman Frank Moore said. Integrated Systems, which developed the B-2 bomber and the Global Hawk unmanned aerial vehicle, accounted for $3.15 billion, or 41%, of Northrop’s sales last year.

Crosby is leaving because in September the company passed him over for the jobs of president and chief operating officer in favor of Ronald Sugar, analysts said.

Shares of Century City-based Northrop rose 27 cents to $93.34 on the New York Stock Exchange. They have risen 13% this year.

Seymour, 51, currently oversees Northrop’s work as a subcontractor on Lockheed Martin Corp.’s new $200-billion Joint Strike Fighter contract, the costliest military program in history.