Atrium has appointed Chris Baker as head of specialty reinsurance. The hire brings one of the London market's most senior treaty underwriters to the Lloyd's insurer as it builds out its reinsurance portfolio under a five-year transformation strategy.
Baker joins from Chaucer, where he serves as head of global reinsurance with responsibility for a portfolio of almost US$2 billion in premium. He brings 22 years of market experience in treaty reinsurance underwriting.
He is expected to join Atrium in July 2027 after completing contractual obligations at Chaucer. He will begin underwriting for the 2028 year of account.
The hire follows Atrium's decision in 2024 to transfer approximately US$196 million in discontinued reinsurance reserves to Enstar's Syndicate 2008. Those reserves covered marine treaty, property treaty and US contractors general liability business. The transaction cleared prior-year liabilities and created conditions for a rebuilt inwards reinsurance portfolio under new leadership.
Atrium CEO John Fowle said the appointment supports the company's strategy to grow its reinsurance portfolio in areas aligned with client demand. He said Baker has deep expertise in managing large, sophisticated treaty portfolios and well-established relationships with clients and brokers. Atrium intends to take a disciplined approach to the expansion.
In March 2026, Atrium appointed James Lakin as head of outwards reinsurance, responsible for the design and placement of the firm's ceded programme. Fowle said at the time that strong reinsurance partnerships remain central to Atrium's ability to deliver consistent returns.
Baker's role is separate from Lakin's. Where Lakin manages Atrium's ceded programme, Baker will underwrite inwards treaty business as a reinsurer.
Baker's July 2027 start date and 2028 year of account entry reflect the contractual notice periods common at senior levels in the London market. Atrium has not specified which specialty lines the new portfolio will target.
Atrium operates through Syndicate 609 at Lloyd's. The rebuilt portfolio under Baker is expected to focus on specialty treaty business consistent with the firm's current risk appetite and client relationships built across proportional and non-proportional lines.
