The payments giant said Curv will help it "accelerate and expand its initiatives to support cryptocurrencies and digital assets."
One source tells CoinDesk that Curv could be sold for as much as $500 million.
The firms aim to build technology that "appeals to traditional institutions, payment providers [and] governments."
Curv is teaming up with MetaMask to allow institutions to invest in DeFi protocols while having institutional-grade custody options.
Franklin Templeton previously tapped Curv to help safeguard its fund by building a transaction signing and management system.
Custody startup Curv is using Compound, the leading lending protocol in DeFi, to help institutions earn interest on idle crypto.
Curv, a company that provides increased secrecy when it comes to holding crypto assets, has closed a $23 million Series A funding round.
Custody startup Curv has expanded into Asia with an office in Hong Kong and a partnership with Japan-based Crypto Garage, the companies announced Friday.