White Mountains Partners Expands Portfolio with BaseSix Acquisition

White Mountains Partners Acquires BaseSix

On April 1, 2026, White Mountains Partners (WMP), a subsidiary of White Mountains Insurance Group, announced its acquisition of a majority interest in BaseSix Systems LLC, a leading provider of complex building systems integration and related aftermarket services. Founded in 2018 and based in Marietta, Georgia, BaseSix specializes in critical low voltage systems including fire and life safety, network wireless, security access control, and audio-visual systems for commercial and institutional sectors.

The acquisition represents a significant step for White Mountains Partners in expanding their portfolio and amplifying their focus on essential services. John Daly, CEO and Managing Partner of WMP, expressed enthusiasm for the partnership, stating, "Basesix was founded with a vision to build a best-in-class multidisciplinary systems integration platform. Under the leadership of co-founders Robb Borden and Chris Atwell, the company’s management team has achieved impressive organic growth and established a strong reputation for delivering high-quality work. We’re excited to collaborate and support their next phase of growth."

Robb Borden, co-founder and current CEO of BaseSix, lauded the efforts of the company's employees in propelling the firm to its current heights. He emphasized that, "We have now reached an inflection point in BaseSix's evolution where the next logical step is to join forces with a strong financial partner to pursue significant growth opportunities, including the opening of new offices and strategic acquisitions." Borden further acknowledged the importance of aligning with a partner that shared the company’s core principles and vision.

The integration intends to leverage BaseSix’s established market presence and expertise, while White Mountains Partners aims to enhance operational capabilities and expand the service offerings available to their clientele. This move will also allow BaseSix to tap into new markets and drive future innovations in building systems integration.

The BaseSix team has adopted a customer-first approach, simplifying complex building systems to create integrated solutions that improve functionality and safety. Their motto embodies the philosophy of transforming technologies into user-friendly systems. This aligns well with WMP’s goal of investing in businesses committed to making meaningful progress and improving service quality.

As part of this transaction, Morgan, Lewis & Bockius LLP served as legal counsel to WMP, while Deloitte Corporate Finance LLC acted as the financial advisor. Miller & Martin PLLC provided legal counsel to BaseSix, solidifying their strategic alliances as they embark on this new journey together.

About BaseSix

BaseSix is dedicated to simplifying building systems by merging various technology disciplines into coherent, user-friendly solutions suited for diverse environments. With an impressive track record, the company aims to make structures safer, smarter, and more user-centric. More information about their services can be found on their website, www.basesix.com.

About White Mountains Partners

White Mountains Partners serves as a vital investment division of White Mountains Insurance Group, Ltd. (NYSE: WTM), focusing on providing essential financial backing to family-owned, founder-led, or entrepreneur-based businesses. WMP’s commitment to supporting initiatives in essential services, specialized consumer sectors, and light industrial markets highlights its strategic approach to investment. Visit www.wtmpartners.com to learn more about WMP’s investment philosophy and portfolio.