Magic Circle firms Slaughter and May and Linklaters have landed lead roles on the biggest-ever insurance deal in southeast Asia.

Hong Kong-based FWD Group Financial Services Pte. Ltd., an insurer backed by tycoon Richard Li, the youngest son of Hong Kong's richest person Li Ka-shing, is acquiring SCB Life Assurance Public Co. Ltd., the life insurance business of Thai lender Siam Commercial Bank Public Co. Ltd., for $3 billion, the largest-ever transaction in the industry in southeast Asia.

The deal is expected to be completed in the second half of this year, subject to approvals by regulators and Siam Commercial Bank's shareholders.