Key Takeaways
- • Cubist, the quant trading arm of Point72, alleges former research lead Xin Jin used AI tools to steal its source code for use at a rival, a claim Jin categorically denies in a sworn affidavit and memo in opposition.
- • Cubist's complaint cites 4,117 individual queries run via Claude Code and Codex that it says extracted information from the firm.
- • Jin seeks approximately $30m from Cubist for compensation and investments made during his tenure, including more than $20m in shares he says he was required to purchase with his bonuses.
- • Cubist treats the money as forfeited because it fired Jin for cause, two days after he disclosed he had accepted another job.
- • Cubist said the claims in Jin's filing are "without merit" and that it will respond in the appropriate legal forum.
Summary
Cubist, the quantitative trading arm of hedge fund Point72, is in a legal dispute with Xin Jin, a former research lead at the firm. Cubist alleges that Jin used AI tools to steal its source code for eventual use at a rival. Jin denies the allegations. In an affidavit and a memo in opposition, he states that he never misused Cubist's confidential information, never used AI tools to take or misuse it, and never "exfiltrated" any AI output, according to eFinancialCareers.
Jin argues that his use of Cubist's AI tools was part of his job, which included monitoring and improving model performance, combining existing models, and generating new research ideas. In his affidavit, he says that reading, reviewing and improving the team's code and research "was my job." He also contends that many of the 4,117 individual queries Cubist cites, run via Claude Code and Codex, were generated by AI agents. He acknowledges repeatedly deleting prompt history and output folders but says this was the removal of hallucinations or unhelpful responses, not an attempt to conceal activity.
Cubist's complaint accuses Jin of "data mining and synthesizing other people's work at Cubist in order to refine it and use it at a rival."
The financial dispute centers on roughly $30m that Jin says Cubist owes him for compensation and investments made during his employment. He states that more than $20m of this consists of shares he was "required to purchase" with his bonuses. Jin says Cubist appears to be treating these amounts as forfeited because it fired him for cause, two days after he disclosed that he had accepted another job.
A Cubist spokesperson said: "The claims in this filing are without merit. We brought this action to protect confidential information, and we will respond in the appropriate legal forum."
Jin argues that his use of Cubist's AI tools was part of his job, which included monitoring and improving model performance, combining existing models, and generating new research ideas. In his affidavit, he says that reading, reviewing and improving the team's code and research "was my job." He also contends that many of the 4,117 individual queries Cubist cites, run via Claude Code and Codex, were generated by AI agents. He acknowledges repeatedly deleting prompt history and output folders but says this was the removal of hallucinations or unhelpful responses, not an attempt to conceal activity.
Cubist's complaint accuses Jin of "data mining and synthesizing other people's work at Cubist in order to refine it and use it at a rival."
The financial dispute centers on roughly $30m that Jin says Cubist owes him for compensation and investments made during his employment. He states that more than $20m of this consists of shares he was "required to purchase" with his bonuses. Jin says Cubist appears to be treating these amounts as forfeited because it fired him for cause, two days after he disclosed that he had accepted another job.
A Cubist spokesperson said: "The claims in this filing are without merit. We brought this action to protect confidential information, and we will respond in the appropriate legal forum."
Go deeper than the headline
Research every firm in this story, track the ones that matter and get the daily briefing — free for 7 days.