Ariel Re has hired Sierra Dietz (pictured above) as underwriter in its property reinsurance division, the latest in a series of moves by the Bermuda-based reinsurer to strengthen its underwriting bench.
Dietz joins from Sompo, where she spent nearly eight years in roles spanning claims, catastrophe modeling and underwriting. She most recently served as reinsurance underwriter, a position she held from March 2025. Before that, she worked as a reinsurance associate underwriter and junior catastrophe modeling analyst at the same firm, having started in 2018 as a claims associate.
Her earlier career included stints at Willis Towers Watson as a graduate trainee and at XL Catlin as an underwriting intern, both in Bermuda. She holds a Bachelor of Business Communications from Brock University and completed an executive development program at the National University of Singapore in 2023.
Dietz's trajectory from claims through catastrophe modeling to underwriting is relatively uncommon but increasingly valued in the reinsurance industry. Claims outcomes represent the best feedback loop for underwriting quality, revealing whether original risk assessments and assumptions hold up in practice.
The challenge is that underwriting and claims often operate in silos. Gen Re, for its part, explicitly maps career paths from claims roles into underwriting and account management positions.
In property catastrophe reinsurance, where a single event can wipe out years of profit, that end-to-end perspective carries particular weight.
The appointment is part of a broader restructuring of Ariel Re's property book leadership. Earlier this month, the reinsurer named Sarah Morgan as head of property reinsurance and Reed Gaglio as head of E&S property reinsurance, both effective April 1. Morgan has been on the property underwriting team since 2006; Gaglio has been with the firm since 2005.
The buildout extends to Ariel Re's Lloyd's operations. Lloyd's approved the firm's newly created Syndicate 2006 to write a 2026 reinsurance book spanning specialty, marine, cyber and clean energy lines. Syndicate 1910 will now focus exclusively on property catastrophe reinsurance, aligning with the firm's ILS peer group in Bermuda.
Ariel Re writes roughly $1.5 billion in premium annually and employs more than 100 professionals across Bermuda, London and Hong Kong. The firm was founded in December 2005 to meet surging demand for natural catastrophe reinsurance after Hurricanes Katrina, Rita and Wilma.
It was acquired in November 2020 by Pelican Ventures, formed by RenaissanceRe founder Jim Stanard, and JC Flowers.
In 2023, the reinsurer secured $270 million of new capital, including $170 million through Lloyd's London Bridge 2 PCC structure, becoming the first sponsor to raise capital through that vehicle.
