About us

Tamesis is a specialty excess of loss reinsurance business.

Tamesis history

Tamesis commenced operations in January 2012 as a Managing General Agency (MGA) writing global specialty excess of loss reinsurance (RI) business on behalf of Tokio Marine Kiln Syndicates 510 and 1880.  Our profitable growth as a reinsurance (RI) MGA has been supported by additional excellent rated capacity, principally through AIG Europe and Ironshore Europe, in 2014.  Supporting our expansion further, National Union Fire Insurance Company and American Home Assurance Company, both US domiciled AIG subsidiaries, gave us the opportunity to create Tamesis Americas in 2016.  We first opened our NYC office and 10 months later, our Miami office to access North & Latin American and Caribbean territories. From 1st April 2018, our AIG capacity in the US is solely written under the American Home Assurance Company stamp to provide for easier management of licensing and regulatory matters across the whole of the Americas binder and continues to provide first class security to our clients.  

Tamesis capacity

We were able to secure the backing of capacity providers which largely hold a credit and financial strength rating of “A+” from S&P and from A.M. Best, Financial Strength Rating of “A” and Issuer Credit Rating of “a”.  This has enabled Tamesis to offer our brokers and clients, excellent quality security.  

In return, our proposition enables investors/capacity providers the opportunity to participate in the global specialty excess of loss and quota share treaty reinsurance market by leveraging our underwriting expertise. We now manage four binders across our business providing bespoke risk and catastrophe management solutions, tailored to the specific risk appetites of each of our carriers.   Consequently the capacity and risk and catastrophe appetite varies from binder to binder.

Tamesis approach

Market Cycles and ‘Value at Risk’ is Key

To our brokers and clients, they value our skilled and experienced underwriting team, and our consistent approach to evaluating business.  Our differentiated underwriting proposition reflects our unique multi-class approach, enabling us to offer capacity where class specific underwriters struggle by the width of coverage being increasingly requested.

The selective approach to underwriting permits increased deployment of capacity in classes where conditions are stronger and facilitates a rapid response to changes in market conditions and proper cycle management.

There is a strict focus on underwriting profit, return on capital, and a 'gross line' underwriting mentality.   We select risks offering the best value to the portfolio in terms of risk adjusted return, class or client.  This has been demonstrated by producing strong returns across the market cycle and “being underweight” to loss exposure during large catastrophe loss events.

Tamesis offers transparency, accountability, integrity, teamwork and consistency of approach.  This enables us to build long-standing, strong relationships with distributors and clients with our unique multi-class position facilitating flexibility and speed of response to changing market conditions.

Tamesis philosophy

  • to offer value based portfolio management, creating a franchise with few peers
  • avoids over-reliance on any single business area 
  • has an effective, pre-emptive and flexible approach to risk management
  • has a conservative, deterministic, top-down view to the aggregation of risk
  • utilises a strategy born of thirty years market experience assessing exposure and buying and designing reinsurance programs 

Meet Tamesis at:


1 Creechurch Place
T +44 (0)20 7337 9888

New York

Wall Street Plaza
88 Pine St. – Suite 2202
NYC, NY 10005
T: +1 (973) 631-7575


1221 Brickell Avenue - Suite 944
Miami, FL 33131
T: +1 480 454 6151