How Jane Street co-founder landed in a coup controversy

New York-based trading firm Jane Street Capital was recently barred from the Indian securities market by markets regulator Sebi which alleged the company used its trading strategies to manipulate stock market, leading to losses for millions of retail investors. Jane Street has rejected the allegation. This is not the first controversy the unusually secretive trading company has run into.

In June, the quiet, secretive world of high-frequency trading was rocked by revelations that Robert Granieri, a low-profile co-founder of Jane Street Capital, was financially linked to an alleged coup attempt in South Sudan. Granieri, a reclusive but powerful figure in finance, claimed he had been duped. But this revelation threw an uncomfortable spotlight on both Granieri and Jane Street Capital, the enigmatic firm he helped create and still influences.

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The South Sudan coup allegations

At the heart of the controversy is Peter Ajak, a Harvard Fellow and economist, who is now being prosecuted in the US for allegedly orchestrating a scheme to overthrow South Sudan’s government and install himself as leader. US prosecutors allege that Granieri, perhaps unwittingly, bankrolled part of this operation. Federal prosecutors in Arizona first charged Ajak and activist Abraham Keech in March 2024 with conspiring to illegally export arms to South Sudan, their home country, to overthrow its government. Both have pleaded not guilty.

"The indictment reads like a cinematic plot: A Harvard Fellow and another activist allegedly wanted to buy AK-47s, Stinger missiles and grenades to topple South Sudan’s government. What they lacked was enough cash," wrote Bloomberg in June.

Granieri’s defense is straightforward: he believed he was funding a humanitarian initiative aimed at promoting democracy and economic growth in the war-ravaged East African nation. He claims Ajak misrepresented the true intent of the project.

As reported by the New York Post in June, Granieri allegedly provided $7 million in two payments after meeting Ajak in February 2024 at a Midtown Manhattan condominium, prosecutors said. Ajak’s lawyers stated in a May court filing, which was reviewed by The Post and first reported by Bloomberg, that Granieri’s financing was “vital to the plan". They claimed in a court document that without his support, the alleged conspiracy would have been impossible. The attorney for the Jane Street founder, whose firm had hired now-convicted fraudster and former FTX CEO Bankman-Fried in 2013, claimed he was misled by Ajak, whom he believed was a human rights activist. “Granieri is a longtime supporter of human rights causes,” his lawyer was quoted by Bloomberg as saying. “In this case, the person Rob thought was a human rights activist defrauded Rob and lied about his intentions.”

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The New York Post further reported that the case also references chess champion Garry Kasparov, though he is not named as a defendant nor accused of any wrongdoing, for allegedly connecting Ajak with Granieri through their shared work with the Human Rights Foundation. Ajak, a former child soldier who resettled in the US, studied at Harvard’s Kennedy School and worked as a World Bank economist before becoming a South Sudanese opposition activist. He and Keech allegedly met with an undercover agent and inspected weapons in a Phoenix warehouse before their arrest, the May 29 motion said. Defense attorneys allege US authorities were aware of the plan, citing a “public authority” defense and claiming that the State Department told Ajak in October 2023 it would not support non-democratic regime change. They also accused prosecutors of selectively targeting Ajak and Keech, both black men, while sparing Granieri and Kasparov.

While the legal system will eventually determine the extent of Granieri’s culpability, the South Sudan controversy marked a rare public misstep for Granieri and Jane Street Capital. For a firm that has thrived on discretion and outsmarting rivals in silence, the spotlight must have been uncomfortable.

Jane Street Capital's bigger controversy
Founded in 2000, Jane Street Capital is a global proprietary trading firm operates across a range of asset classes, including ETFs, equities, bonds and cryptocurrencies. It has earned a reputation for being both highly profitable and fiercely secretive. With headquarters in New York and offices in many countries, Jane Street is a dominant force in the world of quantitative finance. It is known for hiring elite mathematicians, physicists and computer scientists, and cultivating a culture more akin to a university research department than a traditional trading floor.

What sets Jane Street apart is its organizational structure. There is no CEO. Instead, it functions as a kind of technocratic republic, where around 40 senior partners run the firm collectively. Among them, Granieri, the last remaining co-founder still active in the firm, is considered first among equals. Unlike other Wall Street firms that engage with media, public investors, and regulatory frameworks in a highly visible way, Jane Street tends to shun attention. Even internally, information flows are tightly controlled. This secrecy has allowed Jane Street to build advanced trading systems and algorithms without interference or scrutiny.

While allegations against Granieri put it in headlines in June, soon it was hit by a far bigger controversy when Sebi accused it of stock manipulation. Indian regulators have opened a broader probe into Jane Street’s activities, while the company denied any wrong-doing on its part. The ban came after an unusually volatile quarter, where Jane Street reportedly made record profits during a spike in global tariffs. Its revenues rivaled those of Goldman Sachs and Morgan Stanley. That kind of financial firepower has always kept Jane Street in regulators’ crosshairs, but this time, global scrutiny is escalating.

The controversies come at a time when Jane Street Capital is joining the big league. Its net trading revenues hit $20.5 billion last year, up from $2.1 billion in 2019. In the first quarter of 2025, its net trading revenues hit $7.2 billion, surpassing those of Morgan Stanley and within touching distance of Goldman Sachs.