Investor Turns Down Ken Griffin to Build $20 Billion Fund

Hamza Lemssouguer is currently managing $20 billion at his own investment fund after declining a high-profile offer from Ken Griffin, the founder of Citadel.

In 2020, Lemssouguer was approached by Griffin with an offer to manage several billion dollars within the framework of Citadel, one of the world’s most prominent hedge funds.

Lemssouguer chose to turn down the offer from the hedge-fund titan to instead establish and lead his own fund, a decision that has since seen his assets under management grow to $20 billion.

The Role of Ken Griffin and Citadel

Ken Griffin is the founder, chief executive officer, and co-chief investment officer of Citadel LLC, a multinational hedge fund. He also owns Citadel Securities, which operates as one of the largest market makers in the United States.

As of January 2026, Griffin’s estimated net worth was $51.2 billion, ranking him as the 34th-richest person globally.

Griffin’s influence in the financial sector is extensive, and his offer to Lemssouguer in 2020 represented an opportunity to manage a significant portion of capital under the Citadel umbrella.

Strategic Independence in Hedge Fund Management

The decision by Lemssouguer to forgo a position at Citadel highlights a strategic preference for independence over the stability and resources of an established institutional giant.

By launching his own fund, Lemssouguer assumed the risks and rewards associated with independent ownership, ultimately scaling his operations to the current $20 billion mark.

This trajectory reflects a broader trend in the finance industry where high-performing managers seek to capture a larger share of the incentive structure by moving from employee roles to principal roles.