Interactive Brokers LLC (IB) is an American multinational brokerage firm. It operates the largest electronic trading platform in the United States by number of daily average revenue trades. The company brokers stocks, options, futures, EFPs, futures options, forex, bonds, funds, and some cryptocurrencies.

The company is headquartered in Greenwich, Connecticut and has offices in four cities. It is the largest subsidiary of the brokerage group Interactive Brokers Group, Inc., which was founded by Chairman Thomas Peterffy, an early innovator in computer-assisted trading. 

The company is a provider of fully disclosed, omnibus, and non-disclosed broker accounts and provides correspondent clearing services to over 200 introducing brokers worldwide. As of February 2022, the company serves 1.76 million customers, with US$348.5 billion in customer equity.

The original organization was first created as a market maker in 1977 under the name T.P. & Co., and was renamed Timber Hill Inc. in 1982. It became the first to use fair value pricing sheets on an exchange trading floor in 1979, and the first to use handheld computers for trading, in 1983. In 1987, Peterffy also created the first fully automated algorithmic trading system, to automatically create and submit orders to a market. 

Between 1993 and 1994, the corporate group Interactive Brokers Group was created, and the subsidiary Interactive Brokers LLC was created to control its electronic brokerage, and to keep it separate from Timber Hill, which conducts market making. 

In 2014, Interactive Brokers became the first online broker to offer direct access to IEX, a private forum for trading securities. As of 2021, about 23.5 percent of the company is publicly held, while employees and their affiliates hold the remainder; Thomas Peterffy is the largest shareholder.

According to en.wikipedia. Source of photo: internet