Bitcoin multisig custody platform Onramp has raised $12.5 million in a Series A funding round, achieving a pre-money valuation of $135 million. The round was led by Early Riders, with contributions from Onramp's private clients and angel investors. Onramp's custody model involves multiple approvals for Bitcoin transfers, utilizing partnerships with BitGo, Coincover, and Tetra Trust to serve high-net-worth individuals and family offices. The company is expanding its offerings with Onramp Finance, a platform providing Bitcoin brokerage, cash accounts, debit cards, Bitcoin IRAs, and gold access, in collaboration with Bridge, a Stripe subsidiary. Onramp plans to license its custody infrastructure to banks, fintech firms, and exchanges in the future.