Lockheed Martin Corp. signage on the floor at the New York Stock Exchange (NYSE) in New York, US, on Monday, March 9, 2026. Michael Nagle | Bloomberg | Getty ImagesDefense heavyweight Lockheed Martin is leading the race to buy naval defense group Ultra Maritime, CNBC has learned. The deal to acquire Ultra is roughly $3.5 billion, and Guggenheim and JPMorgan are advising on the sell side, according to sources close to CNBC. Ultra is owned by private equity firm Advent International, and specializes in anti-submarine technology. The company makes radar and electronic warfare systems, as well as torpedo defense countermeasures. A Financial Times report last week said that talks were still ongoing and a deal could be announced as early as this week. Advent was reportedly put up for sale earlier in 2026 for more than 3 billion pounds, or $4 billion.Lockheed Martin is one of the world's largest defense firms, producing planes such as the F-35 Lightning II fighter jet and munitions like the Patriot air defense missile. Defense stocks have enjoyed a bumper year in 2026, as conflicts from Ukraine to Iran increase demand for munitions worldwide.In April, the Stockholm International Peace Research Institute said global defense outlays in 2025 climbed to a staggering $2.89 trillion, led by massive spending by European nations.