Much of his (Borgum's) wealth is held in Arthur Ventures, an investment firm he co-founded, according to his 2026 financial disclosure form, which has not been previously reported. Between $18.1 million and $64.4 million of those investments are in AI companies, according to an analysis of the companies' marketing materials shared with ProPublica by public lands advocacy group Save Our Parks. (Government financial disclosure forms allow filers to report wide ranges instead of the specific value of their investments.)