White Mountains Insurance Group, Ltd. (NYSE: WTM) has completed a $125 million structured capital investment into Bishop Street Underwriters. Bishop Street Underwriters is a diversified platform of Managing General Agents (MGAs) and niche underwriting teams focused on the property and casualty insurance sector. Bishop Street, a RedBird Capital Partners portfolio company, achieved over $650 million in gross written premium in 2025. The company also reported industry-leading organic growth and maintained a strong sub-50 percent portfolio loss ratio in 2025. The investment aims to support and accelerate Bishop Street's growth strategy and global expansion in 2026 and beyond.