Kalshi vs Interactive Brokers ForecastTrader

Kalshi vs Interactive Brokers ForecastTrader: the key differences

Kalshi and Interactive Brokers ForecastTrader both list contracts on a CFTC-regulated exchange and clearinghouse, but they’re built for different traders. Kalshi is a standalone exchange with sports, custom combos and the deepest liquidity in the US. ForecastTrader, now branded IBKR Prediction Markets, is Interactive Brokers’ platform for ForecastEx, the exchange it owns, and it focuses on economic data, weather and elections. Kalshi ranks #1 and ForecastTrader #5 in our ranking of the best US prediction markets.

The two also overlap. Since May 14, 2026, IBKR has routed orders to Kalshi and CME Group as well as ForecastEx, sending each order to the exchange with the best net price after fees.

As of September 30, 2026:

• Sports: Kalshi lists sports in most states; court orders block its sports contracts in Nevada, Michigan and Washington. ForecastEx has listed no sports since February 2026.
• Fees: ForecastEx charges a flat 1¢ per contract with no IBKR commission. Kalshi’s taker fee reaches 1.75¢ at a 50¢ price, and most maker orders are free.
• Interest: ForecastEx pays a 3.38% APY coupon on positions. Kalshi pays a 3.25% variable APY on cash and positions for balances of $250 or more.
• Liquidity: Kalshi handled about $53 billion in September 2026, according to The Block. ForecastEx’s volume has fallen about 90% since December 2025, by our tally of its public data.
• Age and funding: Kalshi is open from 18 and takes cards, PayPal, Venmo and crypto. IBKR requires you to be 21 and takes ACH, wire, check or USDC.

Markets

Kalshi covers far more ground. Its public API sorts its markets into 16 categories, from sports and elections to weather, economics, entertainment and mention markets, and combos made up about 62% of its volume in the week of September 14–20, 2026, according to DeFi Rate data.

ForecastEx is built around economic, climate and political questions. Its categories include economic indicators, elections, climate and weather, financial markets, government and technology, plus exchange-listed combos and, since September 22, 2026, conditional contracts. By our tally of its public data, climate and weather made up 63.6% of the contracts it traded in September 2026 (through the 29th), and elections just 3.4%.

• Sports: ForecastEx traded NFL game-winner contracts from November 6, 2025 to January 19, 2026 and NBA ones from January 15 to February 13, 2026, with none since. Whether Kalshi’s sports contracts are reachable through IBKR couldn’t be confirmed.
• Exiting early: ForecastEx doesn’t let you sell; you close a position by buying the opposite side.
• Tools: both offer APIs. ForecastTrader adds TWS algos and a free paper-trading simulator, and Kalshi adds auto-sell and a demo environment for its API.

Fees

For takers on mid-priced contracts, ForecastEx is cheaper; near the extremes, and for most maker orders, Kalshi is. Interactive Brokers charges no commission on ForecastEx contracts, and ForecastEx charges $0.01 per contract on each side of every trade, however the contract resolves. Kalshi’s taker fee is 0.07 × contracts × price × (1 − price), rounded up to the next cent.

The flat fee wins between about 18¢ and 82¢. If you route a Kalshi contract through IBKR, you pay a 1¢ commission plus a 1¢ exchange fee, which IBKR says can be higher or lower in some cases; that’s more than Kalshi’s 1.75¢ maximum taker fee on Kalshi itself.

Worked example: in ForecastEx’s own example, Yes on “Will US Building Permits exceed 1,510,000?” costs 76¢ and wins, so 100 contracts cost $76 plus $1 in fees and pay $100, a $23 profit. A Kalshi taker buying 100 contracts at 76¢ would pay a $1.28 fee, by our calculation.

Both pay interest. IBKR quoted a 3.38% APY coupon on the daily closing value of ForecastEx positions, Yes or No, as of September 30, 2026. Kalshi’s help center lists a 3.25% variable APY on cash and open positions for eligible US accounts with $250 or more. On $1,000 held for a year, that’s about $33.80 versus $32.50 if rates don’t change. Since August 17, 2026, though, ForecastEx has withheld a 50-basis-point administrative clearing fee from the interest before paying coupons, and the exact effect on your coupon is unclear.

Our prediction market fees guide compares all five platforms we rank.

Availability and legality

Both score 9.5 for regulation, but ForecastTrader has the quieter legal picture, partly because it has no sports. As of September 30, 2026, no US state exclusions were found for ForecastEx’s contracts, and no state lawsuits or enforcement actions were found against Interactive Brokers or ForecastEx. It couldn’t be confirmed whether IBKR applies state blocks to the Kalshi and CME contracts it routes.

Kalshi is in the middle of the fight over sports contracts: court orders block them in Nevada, Michigan and Washington, along with more categories in Nevada and Washington, and federal appeals courts are split on whether federal commodities law overrides state gambling laws. The CFTC backs Kalshi and used emergency powers twice on its behalf in 2026.

ForecastTrader is open to eligible Interactive Brokers clients aged 21 and older in the US, Canada, Hong Kong, Ireland and Singapore. Our guide to whether prediction markets are legal tracks the cases.

A CFTC registration doesn’t override a court order in your state. Trade only what’s offered where you are, and don’t use a VPN or false details to get access.

Which should you choose?

Choose Kalshi if you want sports or custom combos, if you’re 18 to 20, if you need deep order books, or if you want to fund with a debit card, PayPal, Venmo or crypto and earn interest on uninvested cash too.

Choose ForecastTrader if you mainly trade economic releases, Fed decisions, weather and elections, if you place mid-priced orders that fill immediately, if you want the 3.38% coupon on positions, or if you already invest with Interactive Brokers.

Using both can make sense for IBKR clients: ForecastTrader covers macro and weather cheaply, while a direct Kalshi account is usually a cheaper way to trade Kalshi’s own markets than routing them through IBKR at 2¢ per contract. Kalshi offers a trading break, self-exclusion and a monthly funding cap; which tools apply to ForecastTrader couldn’t be confirmed, so see our responsible gambling guide.

Read our full Kalshi review and ForecastTrader review, or compare all five platforms in our ranking of US prediction markets.