Who Owns thinkorswim?

thinkorswim was founded in 1999 in Chicago by Tom Sosnoff and Scott Sheridan, options traders who had previously built and sold the brokerage software firm thinkorswim Group's predecessor. Sosnoff, a former market maker on the Chicago Board Options Exchange, set out to build a trading platform for serious retail options traders, at a time when options tools were primitive and geared toward professionals.

The company, originally named Investools for its education business, developed the thinkorswim trading platform with a desktop application known for deep options analytics, probability tools, and customizable charting. The firm acquired and integrated the trading business, adopted the thinkorswim name for the whole company, and went public on the NASDAQ under ticker SWIM in 2007.

In January 2009 TD Ameritrade announced its acquisition of thinkorswim Group for approximately $606 million in cash and stock, completing the deal that June. Under TD Ameritrade, thinkorswim became the broker's flagship platform for active traders and developed a devoted user base known for its paperMoney simulated trading, thinkScript programming language, and deep options chain tools. Sosnoff left in 2011 and later founded the tastytrade media network.

When Schwab's TD Ameritrade acquisition closed in October 2020, thinkorswim became part of the Schwab platform lineup. Client migration ran through 2023, and by early 2024 the platform had fully transitioned to Schwab infrastructure with the TD Ameritrade brand retired. Schwab continued to develop it, adding features and maintaining it as the company's premium offering for self-directed active traders. In 2024 and 2025 thinkorswim experienced high-profile outages during extreme market volatility, including the August 2024 selloff and April 2025 tariff-driven swings, prompting service investment by Schwab.