Xl Fleet Corp
A maker of hybrid and plug-in hybrid electric powertrains that bolt onto existing commercial and municipal fleet vehicles from Ford, Chevrolet, GMC, and Isuzu, letting delivery and utility trucks cut fuel use without buying new ones. Founded in 2009 by MIT alumni as XL Hybrids in Boston, it went public in 2020 and renamed itself XL Fleet. In 2022 it bought the residential solar firm Spruce Power and rebranded to Spruce Power Holding Corporation, leaving vehicle electrification behind.