Steen Associates acted as financial adviser to Sullivan Street on the acquisition of Senior Plc’s Aerostructures division

Sullivan Street Partners, a UK-based private equity investor specialising in mid-market control buyouts, has reached a binding agreement to acquire the Aerostructures business of Senior plc in its largest deal to date for a total enterprise value of up to £200m.

The acquisition comes at a pivotal time for the global aerospace industry, which has record commercial aircraft backlogs due to the sector’s long-term growth. Senior’s Aerostructures business is a premier player in delivering precision-machined airframe and aero engine components and complex assemblies for commercial aerospace, defence and space applications. It has a long track record of excellent customer service and operational delivery across the US, UK and Asia.

With Sullivan Street’s investment, the business will continue to expand its capabilities and scale, with a focus on manufacturing excellence, supply chain reliability and growth alongside its original equipment manufacturing and tier 1 partners. The long-term vision is to build a market-leading supplier that is a valuable and dependable partner to its customers. Leveraging its extensive carve-out and operational expertise, Sullivan Street is working closely with Senior to complete all regulatory approvals and enable a smooth separation of its Aerostructures business. Plans to rebrand the business are underway and will follow in due course.

Steen Associates is advising Sullivan Street on the acquisition of Senior Aerostructures Division for a consideration of up to $275m.

Key aspects of the transaction:

• The transaction was originally announced in July 2025 and represents Sullivan Street’s largest deal to date, with a total EV of up to £200 million or $275 million
• The transaction signed and closed on 31 December 2025 following which the business was rebranded as Zenix Aerospace