Lockheed Martin [LMT] yesterday said it has approved an interim increase of up to $1 billion in its stock buyback program, which is expected to reach its current $3 billion limit before the next scheduled review of repurchase activity.

The current $3 billion share repurchase was established in Oct. 2010 and through the second quarter of 2011 the company has repurchased 27.7 million shares for $2.1 billion, a Lockheed Martin spokeswoman told Defense Daily.

The next review of repurchase activity by the company’s board of directors will occur sometime this fall.

“We believe this additional share repurchase authorization is an effective way to deliver value back to our shareholders and is consistent with our commitment to return at least 50 percent of annual free cash to stockholders,” Bob Stevens, Lockheed Martin’s chairman and CEO, said in a statement.