In 1982, physicist William A. Porter and Bernard A. Newcomb founded TradePlus in Palo Alto, California, with $15,000 in capital.

[5][6][7] In November 2007, Mitch Caplan resigned as CEO and Citadel LLC received a seat on the board of directors of the company after Citadel invested $2.5 billion in the company to bolster its finances after it suffered losses due to the bursting of the 2000s United States housing bubble.

Layton had joined E-Trade's board of directors in November 2007, at the same time as the Citadel LLC deal.

[11][12][13] In December 2009, Robert Druskin, a former chief operating officer of Citigroup, was named interim CEO and chairman.

Idzik had previously been group chief executive of DTZ and also served ten years at Barclays bank.