Gemini is a cryptocurrency exchange owned by the Winklevoss twins that allows customers to buy, sell, trade, and store bitcoins, ethers, and about 40 other assets. It was developed in 2015 by Cameron and Tyler WinklevOSS. Gemini has two services: one for casual investors and one for serious traders. It offers a mobile app, a payment system, and its own currency, the Gemini dollar. Unlike other cryptocurrencies, the Gemini dollar is a "stable coin" linked to the U.S. dollar that is not volatile (unlike Bitcoin). Gemini is a cryptocurrency exchange that competes with companies like Coinbase and Kraken. The company's formal name is Gemini Trust Co., LLC.