The company has over 2,800 employees,[3] with corporate headquarters in Miami, Florida,[4][2]: 1  and offices throughout North America, Asia, and Europe.

[11] In 2006, Citadel and JP Morgan Chase took over the energy portfolio and division of failed hedge fund Amaranth Advisors, which had suffered a 65% ($6 billion) loss in assets.

[20] Citadel under Griffin's leadership was reported as differentiating from hedge funds rivals post-2008 financial crisis with an "aggressive expansion".

[23] In July 2020, during the coronavirus pandemic, Citadel created a "bubble" for a class of 100 interns by renting out a luxury resort in Wisconsin.

[31] In a letter to employees on June 23, 2022, Griffin announced they would be moving their headquarters to Miami, Florida, due to a more favorable business climate and increased crime complaints in Chicago.

In addition, this allowed Citadel to overtake Bridgewater in the list of the most profitable hedge funds in history according to experts from LCH Investments.

[45] However, a month later on December 17, 2008, AM Best announced that New Castle Re's rating was under review when Citadel's funds experienced increased redemption requests as a result of the financial crisis.

[50] Two days later on December 19, it was reported that Citadel would not be renewing the rights in New Castle Re contracts, but that Torus Insurance Holdings in Bermuda would do so.

[53] The firm runs 500 stress tests each day to simulate the impact of potential economic and geopolitical crises or other market dislocation.

[53] Citadel aggregates investment positions on trading screens to calculate "more than 500 doomsday scenarios" to assess the potential of risk for the firm.

[21] In 2014, Citadel rated an A grade for risk management in the annual Institutional Investor Hedge Fund Report Card.

[54] In April 2015, Ben S. Bernanke, who was the United States Federal Reserve chairman for eight years, joined Citadel as a senior adviser on global economic and financial issues.

[60][61] It offered investment management technology, developed internally at Citadel, to a wide range of firms and funds.

[64] In November 2006, Citadel became the second hedge fund to publicly issue bonds to investors in the form of senior unsecured debt totaling $2 billion, in an arrangement managed by Lehman Brothers and Goldman Sachs.

"[67] The New York Times reported in 2010 that "the firm is unique in its reputation for being a revolving door", meaning that it had a high turnover rate.

[69] Citadel has played an active role in regulatory affairs and has advocated for financial legislation on market structure.

In 1999, Congress repealed a provision in the Glass-Steagall Act of 1933 that strictly separated banking and trading activities by financial firms.