The pitch sounded insane in 2018. Two twentysomethings—one a Goldman Sachs alum who'd traded structured credit, the other a Brazilian engineer who'd performed ballet in Austrian opera houses—wanted to build a federally regulated exchange where Americans could legally wager on inflation rates, Congressional elections, even whether it would rain in Des Moines.
Tarek Mansour and Luana Lopes Lara called it Kalshi. Their investors, eventually, called it prescient. By late 2025, the startup commanded a $5 billion valuation and processed more than $1 billion in trades every single week.
Getting there required surviving a regulatory gauntlet that would have buried most founders before their second board meeting.
The two MIT graduates spent their first two years convincing the Commodity Futures Trading Commission that prediction markets weren't just gambling dressed up in financial jargon. They succeeded—Kalshi became the first federally regulated event-contract exchange in November 2020. Then they spent another two years in federal court fighting that same agency when regulators abruptly changed their minds about political betting.
Through all of it, Mansour and Lopes Lara kept building. Perhaps more than they expected.
Today, Kalshi trades more volume than any prediction market globally. By September 2025, it had captured roughly 62% of market share, according to industry data. October's monthly volume hit $4.39 billion, per analytics firm Dune. At Goldman Sachs' recent investor conference in Las Vegas, The Information reported that Kalshi was the undisputed standout—"the king"—with internal metrics showing six-fold volume growth in six months and an annualized revenue run rate approaching $700 million.
Not bad for a company that nearly got regulated out of existence.
When the Regulators Say No, Then Yes, Then No Again
Mansour's résumé suggested he understood the machinery he was trying to disrupt. Computer science and mathematics degrees from MIT. A stint in structured credit at Goldman during the post-crisis years. Global macro trading at Citadel, where he watched billions move on geopolitical shifts and central bank whispers.
Lopes Lara brought something different. The São Paulo native had competed in physics olympiads, earned a prestigious scholarship from Fundação Estudar, and spent years performing ballet professionally in Salzburg before pivoting to engineering at MIT. Both made Forbes' 30 Under 30 Finance list in 2022, though by then the recognition felt almost quaint given what they'd already survived.
The regulatory slog began immediately. After founding Kalshi in 2018 and completing Y Combinator's Winter 2019 cohort, they devoted nearly every waking hour to a single task: convincing federal regulators that event contracts—binary futures paying out based on real-world outcomes—belonged under CFTC oversight, not the patchwork chaos of state gambling laws.
Think of it as futures trading, but instead of corn or crude oil, you're pricing political control or economic data releases. People with actual money at stake, the founders argued, might forecast events more accurately than pollsters with clipboards and dubious sampling methods.
The CFTC agreed. On November 4, 2020, it granted Kalshi designated contract market status, a regulatory seal that meant everything. Four months later, Kalshi raised $30 million in Series A funding led by Sequoia, with strategic backing from Charles Schwab and buyout legend Henry Kravis. The platform launched publicly in July 2021.
"We wanted to create the largest market that could possibly exist," Mansour told Bloomberg's Odd Lots podcast in October 2025. The vision wasn't exactly humble.
But in 2023, ambition collided with bureaucratic second-guessing.
The Case That Almost Killed the Company
Kalshi submitted contracts allowing users to trade on Congressional control—specifically, which party would win the House or Senate in upcoming elections. The CFTC blocked them. The agency's reasoning: these contracts involved gaming and violated nebulous "public interest" standards.
So Kalshi sued.
The case wound through DC District Court for months. Kalshi's argument was deceptively simple: you already approved event contracts, and now you're arbitrarily deciding which events qualify. Judge Jia Cobb sided with the startup, vacating the CFTC's order in September 2024. When regulators tried to appeal and requested a stay, the DC Circuit Court dissolved it on October 2, 2024.
The contracts went live. The timing? Almost surreal.
The 2024 presidential election was weeks away. Traditional polling suggested a virtual toss-up. But prediction markets—Kalshi and its offshore rival Polymarket—consistently showed Trump with stronger odds than any mainstream poll. When Trump won decisively, the markets looked uncomfortably prescient. Pollsters scrambled to explain their miss; prediction market advocates felt vindicated.
"We even overtook Pornhub," Mansour told Wired in November 2024, referencing app-store rankings during election night. For a financial platform, the traffic surge was unprecedented. Mobile app downloads exploded. New users flooded in. And Kalshi's trading volumes went from respectable to extraordinary.
In May 2025, the CFTC voluntarily dismissed its appeal. Mansour called the outcome "historic." It was also, very possibly, the inflection point that turned Kalshi from a well-funded startup into a genuine phenomenon.
The 200x Explosion Nobody Saw Coming
What happened next defies most startup growth curves.
Yahoo Finance reported 200x year-over-year volume growth in October 2025. Weekly volumes that had hovered in the tens of millions during 2024 surged past $500 million by September 2025, according to Dune Analytics. By November, they'd eclipsed $1 billion—and stayed there.
The funding followed. Kalshi raised $185 million at a $2 billion valuation in June 2025, led by crypto-focused Paradigm, with participation from Sequoia, Multicoin Capital, Neo, and Peng Zhao, CEO of Citadel Securities. Four months later—October 2025—the company closed a $300 million round at $5 billion. Andreessen Horowitz and Sequoia co-led. Paradigm, Google's CapitalG, Coinbase Ventures, General Catalyst, and Spark Capital all participated.
That's a 150% valuation increase in four months. Even in venture capital's frothier days, that pace turns heads.
The product evolved too. Politics and economic indicators—the original pitch—became almost secondary. Sports contracts emerged as the platform's largest category by mid-2025. NFL games, NCAA tournaments, Masters golf outcomes. The Financial Times reported that sports contracts alone approached $1 billion in weekly volume by November. Users could trade individual game outcomes, construct parlays, even bet live during games.
Partnerships accelerated distribution in ways that felt almost inevitable once the regulatory dam broke. Robinhood launched a "Prediction Markets Hub" powered by Kalshi in early 2025, starting with policy contracts before expanding to NFL and college football. Webull followed with its own integration in February. Susquehanna International Group became the first dedicated institutional market maker in April 2024—a signal that sophisticated trading firms saw real liquidity.
In November 2025, Kalshi announced something unexpected: a partnership with StockX to create contracts on collectibles and sneaker resale outcomes. Because why not let people trade predictions on limited-edition Jordan values?
When Success Breeds Regulatory Whiplash
Except success also brought a different kind of attention.
State gambling regulators started pushing back. Hard.
Nevada's Gaming Control Board issued a cease-and-desist order on March 5, 2025, demanding Kalshi exit the state by March 14. New Jersey's Division of Gaming Enforcement followed with its own order around March Madness, affecting both Kalshi and Robinhood's integration. Illinois, Montana, and Ohio reportedly sent similar letters, though the details remained murkier.
Then Massachusetts Attorney General Andrea Campbell filed a lawsuit in September 2025, alleging Kalshi operated an illegal sports wagering operation. Traditional sportsbooks and the American Gaming Association lined up behind the argument: sports event contracts are gambling by another name, just repackaged to evade state frameworks that generate tax revenue and fund problem gambling programs.
Kalshi's response has been consistent, almost monotone: federal law preempts state gambling regulations for CFTC-regulated derivatives. End of discussion.
"We are a financial exchange," Mansour told TechCrunch in April 2025. "If the CFTC tells us to stop, we will. If not, we won't."
A federal judge in New Jersey issued a preliminary injunction siding with Kalshi in May 2025, though the broader legal landscape remains uncertain. State attorneys general aren't known for giving up easily, especially when tax revenue and incumbents' lobbying dollars are involved.
What $5 Billion Buys (and What It Doesn't)
The October 2025 funding round came with stated ambitions: international expansion to 140 countries. Kalshi also secured an amended CFTC order in January 2025 permitting intermediated futures trading, essentially opening the door to institutional participants who require clearing and custodial infrastructure.
The platform now offers maker-taker fee structures typical of traditional exchanges—fee rebates in certain markets, tighter spreads, the mechanics that sophisticated traders demand. Dune Analytics integrated Kalshi's verified market and trade data in November 2025, providing transparency that offshore competitors like Polymarket can't easily match.
But perhaps the most telling detail emerged from Goldman Sachs' investor conference chatter. The Information reported whispers of valuation discussions approaching $11 billion—more than double the October round's price. Whether those talks materialize into another funding event or the early scaffolding of a public offering remains unclear.
What is clear: the company Mansour and Lopes Lara started in 2018, armed with little more than regulatory conviction and an almost reckless belief that prediction markets belonged in mainstream finance, has forced a question that regulators, incumbents, and lawmakers can no longer ignore.
If people will always want to bet on the future—and history suggests they will—who actually gets to decide where finance ends and gambling begins? The answer, it turns out, might be worth $5 billion. Or more.
