The week includes the start of March Madness as well as a major partnership between Polymarket and MLB.
As Opening Day of the 2026 Major League Baseball season approaches, Polymarket made history earlier this week with a commercial partnership with the league.
On Thursday, Polymarket announced a partnership with MLB to become the league’s exclusive prediction market exchange partner. MLB joined the NHL, MLS and the UFC as North American sports leagues that have inked commercial partnerships with prediction markets. Last month, MLB Commissioner Rob Manfred briefed team owners on the possibility of a deal with a prediction market exchange.
“It goes without saying that our primary concern, always first in our minds, is protecting the integrity of the game,” Manfred said in a statement.
Amid a contentious battle with numerous state regulators, the US Commodity Futures Trading Commission has asserted that it maintains exclusive jurisdiction over the regulation of sports event contracts. Since his confirmation as CFTC chairman, Michael Selig has consistently reiterated the importance of promoting integrity on derivative markets.
Ahead of the announcement, MLB and the CFTC signed a Memorandum of Understanding on Wednesday. The memo establishes a framework for the CFTC and MLB to discuss, cooperate and exchange information concerning issues of common interest including protecting the integrity of professional baseball and prediction markets, the CFTC wrote in a statement.
“Through this partnership, the CFTC is well-positioned to add additional tools to protect our markets from fraud, manipulation and other abuses. Thanks to MLB and Commissioner Manfred for working with us to protect the integrity of these growing markets,” Selig wrote on X.
Arizona files criminal charges vs. Kalshi
Over the last few months, Kalshi has faced a wave of litigation in state and federal courts around the US. But an indictment unsealed this week in Arizona set a new precedent.
On Tuesday, Arizona Attorney General Kris Mayes filed criminal charges against KalshiEx LLC and Kalshi Trading LLC for operating an illegal gambling business in Arizona without a gaming licence. The 20-count indictment, all misdemeanors, represents the first time that Kalshi has faced criminal charges in the US.
Among the charges are four counts of election wagering, including bets on the 2028 US presidential race, the 2026 Arizona gubernatorial race, the 2026 Arizona Republican gubernatorial primary and the 2026 Arizona Secretary of State race. Arizona law prohibits operating an unlicensed wagering business and separately bans betting on elections outright.
“Kalshi may brand itself as a ‘prediction market,’ but what it’s actually doing is running an illegal gambling operation and taking bets on Arizona elections, both of which violate Arizona law,” Mayes said. “No company gets to decide for itself which laws to follow.”
Kalshi CEO Tarek Mansour critcised the indictments, writing on X: “The Arizona Attorney General’s charges are baseless and a clear overreach. It’s gamesmanship from a politician who’s up for re-election.”
Separately, a Bloomberg report on Thursday found that Kalshi raised more than $1 billion in a new funding round that valued the company at $22 billion. The valuation doubles an $11 billion valuation that the exchange received in December.
Kalshi $1 billion tournament challenge
In 2014, famed investor Warren Buffett offered a near-impossible proposition: If a contestant correctly picked all 63 games in the NCAA tournament, Buffet promised a payout of $1 billion.
Now, more than a decade later, Kalshi is bringing back the challenge. Given the high rate of upsets in March Madness, the odds of filling out a perfect bracket are an astounding 1 in 120 billion. It has not stopped Kalshi from offering the same amount to a customer if they pull off the improbable feat.
In Thursday’s opening round, No. 16 seed Siena nearly upset No. 1 Duke in an East subregional matchup. Siena, the MAAC tournament champion, had a 1% probability to win at tip-off on Kalshi. But the hot-shooting Saints went up 33-22 in the first half en route to an 11-point lead at halftime. By the second half, Siena’s odds topped out at 23%.
Duke, however, commenced on an 11-0 run early in the second half to close the deficit to two. The Blue Devils held Siena to 22 points in the latter half for a 71-65 win. The comeback saved a bevy of users on Kalshi. Duke ranks as the top choice among users to win the tournament, ahead of Arizona, Michigan and Houston.
Approximately 37.3% of all entrants took the Blue Devils to win the title. As of 1:30 pm ET, there were 83 perfect brackets that remained in the contest, according to Kalshi. SIG Parametrics, LLC, a member of the Susquehanna International Group of Companies, is financially backing the promotion, Kalshi wrote.
Matt is primarily responsible for long-form feature coverage on complex sports betting scandals. He also provides coverage on finance, M&A and other technological developments.