TitletownTech, a venture capital firm formed out of a partnership between Microsoft and the Green Bay Packers, has invested in Realta Fusion, a private fusion startup company that was spun out of an ARPA-E-funded fusion project at the University of Wisconsin–Madison in 2022. Realta is developing modular, compact, magnetic mirror fusion energy generators as an economic, zero-carbon solution to power AI-driven infrastructure and other industrial applications. TitletownTech did not disclose the details of its investment.

The magnetic mirror fusion concept dates to the early 1950s, but decades ago it was sidelined by technical difficulties and researchers turned to tokamak fusion in their quest for confinement. Now it’s getting another look—with significantly more powerful technology—through WHAM, the Wisconsin HTS Axisymmetric Mirror, an experiment in partnership between startup Realta Fusion and the University of Wisconsin–Madison.