Senators Elizabeth Warren and John Curtis have given Kalshi and Polymarket until Tuesday 3 November, election day, to say in writing how many suspected cases of insider trading or manipulation they have found on election contracts since 1 January, according to Legal Sports Betting and Bitcoin.com. The letter, dated 28 October and made public on 29 October, is addressed to Kalshi chief executive Tarek Mansour and Polymarket chief executive Shayne Coplan.
Warren, of Massachusetts, is the top Democrat on the Senate Banking Committee. Curtis is a Republican from Utah, the state that filed criminal charges against Kalshi and its two founders on the date the letter bears. Those charges concern sports bets, while the letter concerns election contracts.
This is a request for information. No report we read describes a subpoena, an enforcement action or a finding that either company broke the law, and the cases it cites raise questions without proving how widespread insider trading is.
Coindaro could not read the letter itself, because the Senate sites refused our requests. Its contents below come from the outlets that describe it, which do not all carry the same detail, so each point is attributed to the outlet that reports it.
What the senators ask Kalshi and Polymarket to count on insider trading
Legal Sports Betting and Bitcoin.com both put the number of questions at seven, due in writing. We have not seen their exact wording, and Bitcoin.com gives the fullest account of them.
The first group is about method. According to Bitcoin.com, each company is asked how it keeps people holding nonpublic information off election contracts, a group that includes candidates, campaign staff, election officials and pollsters. The senators also want to know how it stops those people trading through third parties or affiliated accounts, and how it detects wash trading, the practice of trading with yourself to inflate volume. The Hill, in a copy of its report on Yahoo Finance, says the question on prevention reaches beyond the use of Federal Election Commission filings.
The second group asks for numbers. How many suspected cases since 1 January? How many were stopped before the trade, and how many were found afterwards? How many went to the Commodity Futures Trading Commission (CFTC) or to law enforcement?
The split follows from a point the senators make directly. “The identification of isolated instances of improper trading does not demonstrate that these markets are adequately protected,” they wrote, as quoted by Bitcoin.com. A company can publish its catches without saying what it missed, while a before-and-after count would show how often it acted in time.
Kalshi’s four cited cases add up to $9,799.71 in sanctions
The evidence in the letter leans on Kalshi’s own disciplinary record. According to Legal Sports Betting, it points to one 2025 case and three April 2026 cases of candidates trading on their own contests. “These examples raise critical questions about how many election-related transactions have escaped detection,” the senators wrote, in a line quoted by several outlets. Bitcoin.com adds that they cite NPR reporting on campaign staffers trading on internal polling before its release.
The sums are public. The 2025 case is described in a CFTC enforcement advisory of 25 February 2026, and the three others come from Kalshi’s April disclosures, reported by ABC News.
| Case | Kalshi sanction | Suspension |
|---|---|---|
| Candidate traded on his own candidacy, seen in videos from May 2025 | $2,246.36 ($2,000 penalty, $246.36 disgorgement) | Five years |
| Matt Klein, US House race in Minnesota, disclosed April 2026 | $539.85 | Five years |
| Ezekiel Enriquez, US House race in Texas, disclosed April 2026 | $784.20 | Five years |
| Mark Moran, Virginia Senate primary, disclosed April 2026 | $6,229.30, plus disgorgement of any profits | Five years |
Together that is $9,799.71, before whatever profits Moran has to give up, a sum ABC News does not state. For scale, Kalshi has just raised $1 billion at a $40 billion valuation. Moran drew the largest penalty after he, Kalshi said in a statement quoted by ABC News, “repeatedly refused to resolve this matter via settlement”; Klein and Enriquez settled. Moran said on social media that he bet on his race “because I wanted to get caught”.
By its own account, Kalshi sent none of the three April cases to the authorities. “For more serious matters,” its head of enforcement, Robert DeNault, wrote at the time, according to ABC News, “we refer cases to the CFTC or DOJ for further investigation and prosecution, which didn’t happen here.” The CFTC advisory says the sanctioned 2025 trader potentially violated the Commodity Exchange Act, while noting that Kalshi’s internal programme handled the case and that the CFTC has full authority over illegal trading on such exchanges.
The 2025 case predates the 1 January window, so it may not appear in the count. The April cases, disclosed inside the window, could, and a Kalshi reply would show how they sit against the total.
On Polymarket, the letter cites a 2024 wash trading estimate
On Polymarket, the letter reaches back two years. The Hill reports that it cites alleged manipulation during the 2024 presidential election, affecting “roughly one-third of the presidential market’s trading volume” according to a Fortune report. Fortune’s article of 30 October 2024 credits the estimate to the blockchain firm Chaos Labs, which analysed on-chain data and put wash trading at around a third of that market’s volume. That is a private firm’s estimate relayed by the senators, not a finding by a regulator, and Coindaro has not checked it against the underlying data. A Polymarket spokesperson told Fortune at the time that its terms of use “expressly prohibit market manipulation”.
Bitcoin.com says the letter also cites a Wired report from this month on more than $600 million traded on Polymarket contracts about elections in Ethiopia and Romania. The Ethiopian market kept trading for months after the vote, and Polymarket blocked the accounts involved, according to the same account.
Polymarket’s own public figure dates from 27 October, when an executive told NPR it had investigated “dozens” of midterm bets. NPR’s claim of at least two cases sent to the CFTC came from an anonymous source, not from the company on the record. “Dozens” and “at least two” are the loose versions of the figures the senators now want stated precisely.
What Kalshi says, and what Polymarket has not said
Kalshi answered through The Hill. DeNault said the company “proactively blocks candidates and campaign staff from trading to protect market integrity”, and added that while major media outlets have promoted fake polls, “our markets don’t lie”. A source at the company told The Hill that it uses Federal Election Commission payroll data for those blocks, has formed an independent market integrity committee and looks forward to showing how it keeps insiders out.
Polymarket did not immediately respond to The Hill, and we found no reply from it since.
The senators do not sound persuaded in advance. Their letter closes, in The Hill’s account, with doubt that the companies can police these contracts “with effective scrutiny and meaningful accountability”.
Why election contracts draw separate attention
A prediction market lists yes-or-no contracts whose prices move with what traders expect, and Kalshi is regulated by the CFTC as an exchange. Sports contracts are what brought Utah into court. The senators single out election contracts for a different reason: “We are particularly troubled by election-related event contracts,” they wrote, noting according to Bitcoin.com that those contracts get prominent coverage and that some observers read them as a sign of political momentum.
So a distorted price could matter to people who never place a trade. An insider who knows about an unreleased poll or a campaign decision also has an edge that ordinary traders cannot see. That is the concern behind the questions; the reports do not show how often it has happened.
Both senators already have legislation in this area. Curtis has backed a bill with Democratic Senator Adam Schiff to bar CFTC-registered platforms from offering sports contracts, and Warren co-introduced the STOP Corrupt Bets Act in March, according to Bitcoin.com. The letter also follows the Senate’s 30 April adoption of a ban on prediction market insider trading by senators and their staff, Legal Sports Betting reports.
What to watch on 3 November
We do not know whether either company will answer by the deadline, whether a reply will be made public, or what Warren and Curtis plan if the numbers do not arrive. The reports we read mention no penalty for missing the date. Nor is it clear how the totals would be defined, since “suspected” can cover anything from an automated alert to a closed case.
Answers sent on the deadline would reach the senators on election day itself, too late to inform trading before the vote. Polymarket’s latest figure on the record is still “dozens”.
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