Ex-Brevan Howard PM sued over alleged $3.5m unpaid profits

Former Brevan Howard portfolio manager Robert Sicari is facing a lawsuit in New York State Supreme Court from quantitative researcher Wooyoung Hong, who alleges he was denied up to $3.5 million in trading profits and a 30% ownership stake in ThirtyPark Capital. The two established the hedge fund after leaving Brevan Howard in 2024.

Hong alleges that Sicari failed to honor an agreement covering his work at ThirtyPark. Under the agreement described in the complaint, Hong was to receive 50% of the profits from certain trades and a 30% stake in the fund in exchange for developing its trading infrastructure and providing quantitative research support.

The complaint alleges that Hong generated gains through event-driven trades linked to Nippon Steel’s proposed acquisition of U.S. Steel, Chevron’s takeover of Hess and the merger between Paramount and Skydance.

Hong claims the U.S. Steel-related trades produced returns of about 80%, entitling him to between $1.2 million and $2 million. He estimates that his unpaid compensation for work performed from November 2024 through December 2025 could reach $3.5 million.

According to the lawsuit, Sicari later proposed changing the arrangement to a $400,000 cash payment and a 30% profit share that would vest over time. The complaint says Sicari cited the need to preserve capital while the fund was starting operations.

Hong rejected the proposed terms, according to the filing. Sicari then revoked Hong’s access to ThirtyPark’s trading systems in January, the complaint alleges. Hong claims he received $20,000 for more than a year of work.

Sicari confirmed that ThirtyPark Capital is no longer operating and declined to comment further on the allegations. His lawyer also declined to comment. Brevan Howard, which is not a party to the case, declined to comment.

Sicari and Hong previously worked together at Brevan Howard, where Sicari managed a portfolio worth hundreds of millions of dollars. Hong, a Harvard-trained physicist and former Google employee, joined the firm in 2023 on a reported base salary of $400,000.