Founded in 1975 and headquartered in Omaha, Nebraska, TD Ameritrade grew to become one of the largest online brokers in the United States. The company pioneered several innovations in the financial services industry, including being one of the first to offer touch-tone phone trading and later, internet-based trading. It is renowned for its comprehensive investment offerings, educational resources, and its advanced trading platform, thinkorswim. In October 2020, The Charles Schwab Corporation completed its acquisition of TD Ameritrade, and the two firms are currently in the process of a full integration, moving all TD Ameritrade clients and services onto the Charles Schwab platform.