Kalshi, Polymarket lobby as insider trading, betting eyed by Congress

With proposals to rein in prediction markets proliferating through the halls of Congress in recent weeks and months, Kalshi — one of the biggest players in the booming industry — went on defense.

The New York-based platform launched an ad campaign throughout Washington, rolling out mint-green spreads on billboards, bus shelters and inserts in The Washington Post. The ads seek to deflect the spate of criticism being hurled Kalshi’s way and to position it as different from Polymarket, the other global industry giant.

“We ban insider trading,” “We don’t do death markets,” “We aren’t the house,” “We operate under U.S. law,” the ads read.

The companies are looking to get ahead of lawmaker concerns about insider trading and bets placed on things like war-related deaths.

Building corporate influence in the capital city is a well-used playbook. Prediction markets are a new player, and Kalshi and Polymarket are working to create goodwill with Congress and regulators, who are raising concerns about insider trading and unseemly bets on the platforms.

“There’s been a lot of conflation between the two big prediction markets players,” Kalshi’s head of communications Elisabeth Diana said in an interview. “There are very big key distinctions between the two, and we want to make sure the public — and more importantly policymakers — understand the difference.”

“What we are focused on is building the best product, setting the standard on these issues and working with our relevant regulators and law enforcement to appropriately draw the lines and enforce against actual bad actors,” Olivia Chalos, deputy chief legal officer at Polymarket, said in an interview. Chalos declined to directly address Kalshi’s messaging.

Prediction markets including Kalshi and Polymarket have surged in popularity in the last year. The markets allow users to purchase event contracts — essentially, bets on the outcome of a specific event — on a variety of areas, including sporting events, awards shows and elections.

Kalshi dominates the U.S. prediction market space, accounting for roughly 90% of U.S. market share, according to an April 8 Bank of America report. Polymarket is a major global player but has a limited U.S. footprint.

Sports are the most popular event contract type by volume — as of February, almost 90% of bets made on Kalshi in the last year were on sports, according to the Congressional Research Service — though users in some cases are able to place bets on more controversial issues, which has led to increased scrutiny.

One user on Polymarket raked in $400,000 in January by correctly predicting the ouster of Venezuelan President Nicolás Maduro, raising insider trading concerns. Subsequent bets…