Japanese giant Sompo has completed its takeover of island-based insurance and reinsurance firm Endurance Specialty in a $6.3 billion deal.

Now Endurance will be integrated into Sompo Holdings through the creation of Sompo International, which will be based in Bermuda.

Sompo International will have its own board, led by Endurance’s John Charman, as chairman and chief executive, reporting to the Sompo president and CEO Kengo Sakurada.

Mr Sakurada said: “The closing of our acquisition of Endurance marks the beginning of an exciting new chapter in Sompo’s story.

“The integration of Endurance within Sompo International will significantly enhance Sompo’s presence in international markets and provides the group with greater opportunities to deepen and expand its geographic footprint by offering global diversification via its new and new and innovative structure leading to global integration.

“Clients will benefit from our increased scale, expanded product offering and a common underwriting platform. Our employees will also be presented with new opportunities to use and develop their skills within a much larger, stronger business.

“I would like to welcome John Charman and the Endurance team to the Sompo family. John will be heading Sompo International, creating our exciting new global commercial insurance and reinsurance platform. I look forward to working closely with him as we embark on the next phase of our exciting growth.”

Mr Charman added: “I am fully committed to our shared vision of future growth for SOMPO’s international platform and I am looking forward to developing it further alongside Endurance’s executive leadership team and my new colleagues under the new Sompo International brand.

”I would like to thank our highly valued partners and colleagues for their loyalty, support and trust over the last few years and I look forward to working closely with them in the future.”

The deal was announced late last year, but was subject to approval by regulators.

Sompo International will also encompass Sompo’s existing international commercial insurance and reinsurance businesses.

The creation of a common underwriting platform and systems is designed to “set a new global standard of conducting business, providing customers with a wide array of products across insurance markets to help manage their risks”.

All Endurance business, with the exception of ARMtech, will be conducted under the Sompo International brand.

Sompo America and SJNK Europe will also be rebranded Sompo International.

Sompo Canopius will remain as a separate brand, working in close collaboration with Sompo International.

AM Best yesterday removed Endurance’s “under review with positive implications” rating and upgraded Endurance Specialty Insurance’s financial strength rating from A (excellent) to A+ (superior) following the acquisition announcement.

AM Best said: “The ratings actions reflect the operational benefits that Endurance will derive from being a significant operation within a larger organisation with deep financial resources.”

The ratings agency also moved Endurance’s long-term issuer credit ratings to aa- from a.

Parent Endurance Speciality Holdings saw its long term issuer credit ratings and the long term issue credit ratings to a- from bbb with a stable outlook.