Tokyo-based insurer Tokio Marine Holdings Inc announced a strategic partnership with Warren Buffett's Berkshire Hathaway, selling a 2.49% stake through a third-party allotment of treasury shares.

The deal is expected to raise up to 287.4 billion yen ($1.8 billion), which will be used to repurchase company shares and prevent dilution for existing shareholders.

Berkshire's reinsurance subsidiary, National Indemnity, will hold the initial stake and agree not to acquire more than 9.9% of Tokio Marine's shares without board approval.