Is Kalshi legal in Wisconsin?

Attorney General Josh Kaul filed a complaint to abate a public nuisance in Dane County Circuit Court on April 23, 2026. It names five Kalshi companies (Kalshi, Inc., KalshiEX, Kalshi Klear, Inc., Kalshi Klear, LLC and Kalshi Trading), three Robinhood companies, two Coinbase companies and twenty unnamed defendants (summons, p.1). It was one of three complaints the Department of Justice announced that day; the others name Polymarket and Crypto.com.

The complaint says Kalshi, Robinhood and Coinbase "are working together to facilitate illegal sports betting throughout the state" (p.2, ¶2). It says a sports event contract is "indistinguishable from an ordinary sports bet, as defined by Wis. Stat. § 945.01(1)" (p.2, ¶5), and that because each company collects a fee on every trade, each is "engaging in criminal gambling activity under Wis. Stat. § 945.03(1m)" (p.3, ¶¶6-8). That statute makes commercial gambling a Class I felony; the complaint asks for civil relief, a declaration and an injunction, not a criminal penalty. Its one claim is public nuisance, based on § 945.03(1m)(b), (c) and (g) (pp.30-33).

The complaint notes two exceptions: tribal gaming compacts let certain tribes run sports betting on their lands, and state law allows some electronic sports wagers through servers on tribal lands. It says neither covers non-tribal operators (p.14, ¶¶46-47). These are the state's allegations. No court has ruled on them.

The state asks for a declaration that, "by making sports-related event contracts available for trading by customers located in Wisconsin," the defendants are violating § 945.03(1m)(b), (c) and (g) and causing a public nuisance, and for a preliminary and permanent injunction barring them from making sports-related event contracts available to customers located in Wisconsin (pp.33-34). The request names no other kind of contract and asks for no damages, penalties or restitution.

On open positions, the complaint's last footnote says: "The State does not seek to void or otherwise invalidate outstanding sports-related event contracts where a customer located in Wisconsin is a party; the State seeks only the prospective relief described" (p.34 n.20). That is what the state asks for, not a court order. No order we found addresses withdrawals, deposits or open positions.

On April 24, 2026, Kalshi's five companies removed the case to the U.S. District Court for the Western District of Wisconsin, No. 3:26-cv-00378, with Robinhood's and Coinbase's consent (notice of removal, ECF 1, p.1). The notice argues the contracts are swaps under the Commodity Exchange Act and that the CFTC has exclusive jurisdiction over trading on a designated contract market (¶¶1-2, p.2).

Three requests followed, and we could not determine whether the court has ruled on any of them:

• Send it back. The state moved to remand the case to state court on May 14 (ECF 27).
• Move it to the Eastern District. Robinhood moved on May 19 to transfer the case to the Eastern District of Wisconsin, where the CFTC's suit against the state is pending (ECF 41). Kalshi and Coinbase joined the motion (ECF 66, p.3, June 10).
• An injunction. The state moved for a preliminary injunction against sports-related contracts on June 9, and asked for a ruling "only in the event the Court denies its Motion to Remand" (ECF 62, p.1). On June 24 the defendants asked, without the state's opposition, for their response to be due July 10 and the state's reply July 24 (ECF 69, p.3). That filing says no hearing had been scheduled (¶5, p.2).

The filings we could read stop at June 24. A later complaint by another company, filed August 14, describes all three Wisconsin cases as "now pending in this District" (Novig complaint, ¶83, p.27). That is the company's description, not an order. Appeals from Wisconsin's federal courts go to the Seventh Circuit.

On April 28, 2026 the CFTC sued Wisconsin "in response to the state's lawsuits against Kalshi, Polymarket, Crypto.com, Robinhood, and Coinbase." Its position is that Congress gave the CFTC exclusive jurisdiction over event contracts traded on designated contract markets. The case is CFTC v. Wisconsin, No. 2:26-cv-00749, in the Eastern District of Wisconsin; the defendants' filings in Kalshi's case call it United States v. Wisconsin and place it before Judge William C. Griesbach (ECF 66, p.3). We could not read its docket.

A September 11 order from the Western District of Wisconsin reports a July 29, 2026 ruling in that case and quotes it as finding that the "CFTC has not shown that it is likely to prevail on its argument that the CEA's definition of 'swaps' covers the event contracts offered by entities such as Kalshi" (Ho-Chunk order, p.3). We could not read the ruling, so we cannot say what it ordered or whether it has been appealed.

Kalshi's position, wherever states have challenged it, is that its contracts are derivatives on a CFTC-designated contract market and that federal law overrides state gambling rules for them. The federal courts that have ruled disagree, as the same September 11 order notes (p.3). On one side it lists the Ninth Circuit's August 28 ruling for Nevada and the July 29 Eastern District of Wisconsin ruling it reports; on the other, the District of Minnesota's July 27 ruling granting Kalshi a preliminary injunction. All of these are preliminary rulings on federal commodities law, not tax rulings, and the question is open. Kalshi at the Supreme Court follows the petitions, and is Kalshi gambling? sets out both sides.

Four other Wisconsin matters touch Kalshi or prediction markets.

The Ho-Chunk Nation. The Nation sued Kalshi and Robinhood in the Western District of Wisconsin in 2025 (No. 3:25-cv-00698), claiming Kalshi's sports contracts are unlawful gaming on its tribal land under the Indian Gaming Regulatory Act. On May 11, 2026 Judge William M. Conley dismissed the Lanham Act and racketeering claims, kept the tribal-gaming claim, and denied a preliminary injunction: he found the Nation likely to succeed on that claim but found no irreparable harm (opinion, pp.2, 29). On September 11 he certified the May ruling for an appeal and stayed the case while the defendants seek one (order, pp.7-8). The case concerns tribal land, not the state's suit, and no injunction has issued.

The Elections Commission. A July 9, 2026 staff memo to the Wisconsin Elections Commission, which names Kalshi and Polymarket, says staff believe Wis. Stat. § 6.03(2), which bars a person who has bet on an election from voting in it, "includes making trades on election-related prediction markets," and recommends a press release to voters (pp.3-4). That is the staff's reading, not a court ruling. We could not read the Commission's release itself.

State employees. Governor Tony Evers's Executive Order 294, signed May 14, 2026, bars state executive branch employees from using nonpublic information obtained through their work to profit or avoid loss on prediction markets. It names no company.

Other companies' suits. Ludlow Exchange, which does business as Novig, sued the attorney general and the state's gaming administrator on August 14, 2026, asking a court to block enforcement of Wisconsin's gambling laws against its event contracts (No. 3:26-cv-00761). Kalshi is not a party. Wisconsin's separate case against Polymarket is covered on is Polymarket legal in Wisconsin?.

We found no order aimed at Robinhood or Coinbase customers in Wisconsin. Both are defendants in the same case as Kalshi, and the complaint describes Robinhood and Coinbase customers placing orders that are executed on Kalshi's exchange (pp.23-24, ¶¶70-72). The state dismissed Robinhood Securities on May 29 (stipulation, ECF 52). The defendants' June 24 filing lists Kalshi's five companies, Robinhood Derivatives and Coinbase Financial Markets (ECF 69, p.1). The relief the state asks for is the same for all of them: no sports-related contracts for customers located in Wisconsin.

Nothing in the case addresses federal tax, and a state gambling case isn't a ruling on federal income tax. How Realize rebuilds gains and losses from Kalshi's data is in how to file Kalshi taxes, and every other state is on the Kalshi legal page.