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.

Total raised

$34M

Funding rounds

2

Latest round

Series A

Latest activity

May 2026