U.S. government contractor L-3 Holdings Inc. on Monday announced it has been selected to take part in a government contract to upgrade information technology gear and services in civilian and defense agencies.

L-3 is one of 29 companies chosen by the General Services Administration, the government's main purchasing agency, for its Alliant contract, a five-year contract with five one-year options and an overall potential value of 50 billion U.S. dollars.

Companies selected to participate in the contract are not guaranteed work, but must bid on specific project orders issued by agencies. The contract covers most technology services, such as computer design, software engineering and systems integration, the GSA has said.

Other companies selected to participate in the Alliant contract, as announced last month by GSA, include AT&T Inc., Electronic Data Systems Corp. and General Dynamics Corp.

Shares of L-3 dropped 1.41 dollars to 98.17 dollars in afternoon trading Monday.