Advent International is exploring a potential sale of Ultra Maritime that could value the business at more than £3 billion or approximately $4 billion, according to Bloomberg sources. The company specializes in anti-submarine warfare technologies including sonar systems, sonobuoys for submarine detection, and torpedo countermeasure systems.

Ultra Maritime supplies naval forces across major defense markets including the US, UK, Canada, and Australia. Advent gained control through acquisitions of UK defense groups Cobham and Ultra Electronics Holdings, subsequently divesting several assets. In June, the firm sold Ultra PCS, which produces missile ejection systems, to Eaton for $1.55 billion.

The potential sale comes amid surging investor interest in defense assets as governments increase military spending due to rising geopolitical tensions. The European Union has pledged hundreds of billions of euros to strengthen regional defense capabilities and reduce reliance on US military systems. Maritime defense technologies have become particularly critical as naval security grows more important amid global conflicts and underwater infrastructure concerns.