SAIC Inc. (SAI), which provides technology services to the U.S. government, has protested the loss of its biggest federal contract to Lockheed Martin Corp. (LMT)

Lockheed, the nation’s largest defense contractor, on June 15 beat SAIC for the Defense Department contract valued at as much as $4.6 billion to operate a communications network known as the Global Information Grid.

SAIC filed its challenge on June 22 with the U.S. Government Accountability Office, which arbitrates contract disputes. Shares of the McLean, Virginia-based company fell 1.2 percent to close at $11.72 in New York trading. Its shares have fallen 4.6 percent this year.

“We are disappointed in the government’s decision to not award us” the contract, Melissa Koskovich, a spokeswoman for SAIC, said in a statement late yesterday. “We feel our solution is the best value for the customer and we are proud of our performance history on this contract.”

SAIC gets more than 90 percent of its revenue from work for the federal government. The company had $10.6 billion in revenue in its fiscal year ended Jan. 31.

The contract is for as long as seven years if all options are exercised, and its estimated value for the three-year base period is $1.91 billion.

SAIC, the eighth-largest contractor on the Bloomberg Government top 200 list, has received at least $3.6 billion for the work since 2001, according to data compiled by Bloomberg.

To contact the reporter on this story: Nick Taborek in Washington at ntaborek@bloomberg.net

To contact the editor responsible for this story: Stephanie Stoughton at sstoughton@bloomberg.net