Sompo Holdings will pay $US6.3 billion ($8.3 billion) in cash to buy Bermuda-based Endurance Specialty Holdings, which has huge operations in the US and UK.

The deal marks the Japanese insurer’s largest acquisition and underlines its ambition to grow its overseas footprint, to make up for sluggish growth at home.

The US, in particular, is attractive because it is the world’s largest insurance market.

“Endurance brings strength in the primary insurance business in developed markets,” Sompo Holdings President and CEO Kengo Sakurada said.

“This acquisition will be integral in helping Sompo realise its goal of providing insurance and related services of the highest quality that contribute to the security, health and wellbeing of its customers.”

Endurance was established in 2001 in Bermuda, providing property, casualty and specialty lines of insurance and reinsurance.

It made $US344 million ($452.7 million) in consolidated net income last year.

The acquisition is expected to complete before March next year, subject to regulatory and shareholder approval.