Ken Griffin, the CEO of Citadel and one of Wall Street’s most outspoken investors, was born in 1968.

In 1987, at the age of 19, Griffin started his first hedge fund with $265,000 in Cambridge, Massachusetts. He successfully convinced his first investor, a friend in the broking industry.

In December 1990, Kenneth Griffin founded Citadel LLC, his most famous undertaking, which achieved over 40% profit for its investors in the first two years.

Citadel, originally named Wellington Financial Group after its flagship fund, changed its name to Citadel in 1994.

In 1998, Citadel started requiring investors to accept terms that restricted their ability to withdraw their capital, a move that proved beneficial during the collapse of Long Term Capital Management.

In 2004, Citadel founded CIG Reinsurance Ltd, a Bermuda-based catastrophe reinsurer providing $450 million in capital, to enter the reinsurer industry and diversify its investment strategies.

In 2005, Citadel founded New Castle Re, a $500 million reinsurer, to capitalize on rising reinsurance prices post-Hurricane Katrina and further diversify its investment portfolio.

In November 2006, Citadel became the second hedge fund to publicly issue bonds totaling $2 billion in senior unsecured debt.

In May 2007, a profile of Ken Griffin, the founder and CEO of Citadel, was featured in Portfolio Magazine, shedding light on his private nature and limited media interactions.

On October 31, 2008, Citadel announced the shutdown of its fund of funds portfolio called Fusion, which was initiated 18 months earlier with mostly the firm's own capital.

In November 2008, New Castle Re, founded by Citadel, received an 'A−' rating from AM Best, showcasing its financial strength in the reinsurance industry.

On December 19, 2008, Citadel announced it would not renew the rights in New Castle Re contracts, leading to Torus Insurance Holdings taking over the renewals.

In January 2009, Citadel placed New Castle Re into run-off, marking the end of its operations in the reinsurance industry.

In June 2009, Kenneth C. Griffin, the founder and CEO of Citadel, was given a seat on E*TRADE's board of directors as part of the 2007 Citadel investment agreement.

In September 2009, Citadel decided to sell a part of its original investment in E*TRADE to reduce its exposure to a single investment and also decreased its 'Level 3' assets.

In 2010, Citadel's Kensington and Wellington funds saw returns of 10 percent, indicating a positive trend in their performance.

On January 17, 2012, Citadel's flagship funds crossed their high watermarks, recovering from the losses incurred during the 2008 financial crisis.

On June 30, 2013, a 13F-HR/A form was filed. This form provides information about the holdings of institutional investment managers.

On August 14, 2013, a 13F-HR form was filed. This form discloses the securities holdings of institutional investment managers.

On March 31, 2014, a submission of 13F-HR/A was made.

On May 15, 2014, a submission of 13F-HR was made.

On August 8, 2014, a submission of 13F-HR/A was made.

On February 6, 2015, a submission of 13F-HR/A was made.

On May 15, 2015, a submission of 13F-HR was made.

On June 26, 2015, a submission of 13F-HR/A was made.

On August 7, 2015, a submission of 13F-HR/A was made.

On March 31, 2016, a submission of 13F-HR/A was made. This filing discloses the holdings of institutional investment managers, including changes from previous filings.

On June 30, 2016, a submission of 13F-HR was made. This filing discloses the securities holdings of institutional investment managers.

On August 12, 2016, a submission of 13F-HR was made. This filing provides detailed information about institutional investment managers' holdings.

On January 31, 2017, a submission of 13F-HR/A was made. This filing provides information about institutional investment managers' holdings.

March 31, 2017 marked the submission of a 13F-HR form, providing financial insights.

June 30, 2017 saw the submission of a 13F-HR form, disclosing financial data.

August 11, 2017 marked the submission of a 13F-HR form, providing insights into financial holdings.

On September 30, 2019, financial activities took place.

On March 31, 2021, a submission of 13F-HR/A was made.

In May 2021, Gary Gensler reiterated concerns about Citadel Securities' role in the GameStop short squeeze event during his testimony to the House of Representatives Financial Services Committee.

An amendment to the 13F-HR was made on May 21, 2021.

On August 16, 2021, a submission of 13F-HR was made.

Citadel was ranked as the second top hedge fund manager in terms of net gains since its inception as of December 31, 2021.

In June 2022, Kenneth Griffin announced that Citadel would be relocating its headquarters to Miami, Florida, citing a more favorable business environment and concerns over crime in Chicago.

LCH Investments NV's Citadel has been ranked as the number one hedge fund manager in terms of net gains since its inception until December 31, 2022.

By September 30, 2023, Citadel held approximately 21.16 million shares of Boston Scientific Corp., making up a notable portion of its total portfolio. The fund's investment in Boston Scientific has seen positive returns, reflecting Citadel's strong investment strategies.

On November 14, 2023, a 13F-HR form was filed, reporting holdings with a total value of $14203 as of September 30, 2023.

LCH Investments NV's Citadel has been ranked as the top money manager in terms of net gains since its inception until December 31, 2023.

On February 14, 2024, a 13F-HR form was filed, reporting holdings with a total value of $500,320,816 as of December 31, 2023.

As of September 30, 2024, Citadel owned approximately 5.04 million shares of Microsoft Corp. and 15.02 million shares of Activision Blizzard. These holdings accounted for significant portions of Citadel's total portfolio, showcasing the fund's strategic investment decisions.