White Mountains Partners ("WMP"), a White Mountains operating company, announced today that it has acquired a majority interest in BaseSix Systems LLC ("Basesix" or the "Company"), a provider of building systems integration and aftermarket service.  Founded in 2018 and headquartered in Marietta, Georgia, Basesix provides the design, installation, retrofit, maintenance, and repair of mission critical, low voltage building systems for commercial and institutional customers across the fire & life safety, network & wireless, security & access control, and audio-visual disciplines.