Participated · Series A · May 2026

Magrathea develops a next-generation electrolytic process to extract magnesium metal from seawater and waste brines with a goal of producing carbon-neutral magnesium. The company operates a pilot facility in Oakland, California and is led by CEO Alex Grant. Magrathea positions its product to reduce reliance on traditional mining and on Chinese supply chains for magnesium. Following the Series A, the company intends to expand operations and continue development work, including building a demo smelter. Financially, Magrathea has just completed a $24M Series A; no revenue or user metrics were reported.

Led · Seed · Sep 2025

Dig Energy has developed a compact water-jet drilling rig intended to dramatically reduce the upfront cost of shallow geothermal ground loops for heating and cooling. The founders, Dulcie Madden and Thomas Lipoma, spent about five years in stealth refining the design and drilling test holes through various soils and rock types near their New Hampshire offices. The company claims its rig can cut drilling costs by up to 80% and produces straighter holes that can be placed closer together than those from conventional rigs. Dig plans to sell its rigs to drillers and is preparing a slightly larger production version for initial commercial pilots supported by its recent seed round. The startup is positioning its technology to enable broader adoption of geothermal by making rigs small enough to access constrained sites such as backyards and crowded commercial lots.

Participated · Series A · May 2025

Realta Fusion is building CoSMo fusion™, a compact, scalable and modular magnetic-mirror fusion system that traps super-heated hydrogen between high-field magnets to generate carbon-free heat or electricity for industrial users such as data centers, chemical processors, metal recyclers and remote mines. The company spun out of a U.S. Department of Energy ARPA-E–funded experiment at the University of Wisconsin-Madison that set a 17-Tesla magnetic-mirror field record using high-temperature superconducting magnets. CEO and co-founder Kieran Furlong positions Realta’s approach as a lower-capital path to commercial fusion compared with alternative concepts. Current work focuses on de-risking the physics of its reactor while progressing toward commercialization. Financially, Realta recently closed a $9.5 million growth capital debt facility from Silicon Valley Bank, adding to a $36 million Series A led by Future Ventures and a 2023 seed round led by Khosla Ventures (undisclosed size). These funds provide runway for continued technology validation and system development.

Participated · Equity · Jan 2021

MadeiraMadeira is an online marketplace specializing in home products, offering roughly 300,000 products and combining third-party sales with private-label goods and its own shipping and logistics. The platform hosts more than 10,000 sellers and about 2.5 million SKUs, and has added physical showrooms while keeping orders online. The company benefited from COVID-19 tailwinds as ecommerce penetration in Brazil rose from roughly 7% pre-pandemic to 17% at the peak and has since stabilized around 10%. MadeiraMadeira operates ten warehouse locations today and employs over 1,300 people, most focused on technology, logistics and product development. Recent financing valued the business at over $1 billion and the company plans to use proceeds to expand logistics capacity, add new warehouses, introduce same-day delivery and grow private-label services. Management positions these moves as consolidation of its leadership in Latin America’s home goods market and as preparation for a potential public offering.