(Reuters) -Lockheed Martin on Tuesday forecast it will make less profit than expected in 2025, as the top U.S. defense company grapples with the delayed rollout of upgrades to the F-35 fighter jet that are vital to its bottom line. 

Shares of the company fell about 8.2% in premarket trading after the company told investors of new financial losses on classified programs and said the F-35 jet software problems dogging the company may last into 2026. Shares were last down 7.6% on the day.

The F-35 is the most expensive U.S. defense program and easily Lockheed's biggest revenue generator, contributing about 30%.

Lockheed has been navigating delays in rolling out a technology upgrade to give the jet better visual displays and processing power under the Technology Refresh 3 program.

U.S. defense contractors are seeing a surge of weaponry demand due to the Russia-Ukraine war and conflicts in the Middle East, but are straining to meet demand amid a slower recovery in pandemic-related supply issues.

The Bethesda, Maryland-based company expects profit per share to be between $27 and $27.30 in 2025, missing analysts' average estimate of $27.92 per share, according to LSEG data.  

In the fourth quarter, Lockheed posted net income of $527 million, or $2.22 per share, a 71% slide from a year ago, as it booked $1.29 billion in losses associated with classified programs at its aeronautics and missiles and fire control business units. The losses came on fixed-price contracts where Lockheed agreed a price with the customer but Lockheed's costs went up, forcing the defense firm to perform the work at a loss.

Arms makers are likely to get a boost under U.S. President Donald Trump's administration, which is expected to increase defense spending. 

But the formation of the Department of Government Efficiency headed by billionaire Elon Musk, who has indicated that Pentagon spending and priorities will be a target of the efficiency initiative, has soured investor sentiment.

The billionaire has also criticized legacy defense programs like Lockheed Martin's F-35 fighter jet while calling for mass production of cheaper AI-powered drones, missiles and uncrewed submarines.

Lockheed said it expects to deliver between 170 and 190 F-35s in 2025.

Its aeronautics business, which makes the jet, reported a 40% drop in operating profit in the fourth quarter. 

Lockheed's total sales of $18.62 billion in the quarter were marginally lower than a year earlier.