- Polymarket’s trading volume fell 8.9% in April to $10.2B — its first monthly decline since August 2025 — while rival Kalshi surged 13% to $14.8B.
- Active traders on Polymarket dropped 12% (733K to 643K), and a botched V2 upgrade wiped all open orders for over an hour.
- Kalshi raised $1B at a $22B valuation; Polymarket is reportedly in talks at just $15B — a $7B gap that reflects diverging momentum.
The prediction market leaderboard has a new name on top, and it’s not the one most people would have bet on. Polymarket’s trading volume fell 8.9% in April to $10.2B while Kalshi rose 13% to $14.8B, marking the first time since last August that Polymarket posted a monthly decline. The sector as a whole grew 12.4% to $29.8B — Polymarket just isn’t capturing the upside.
The user numbers tell the same story. Active traders on Polymarket dropped from roughly 733,000 in March to about 643,000 in April, a 12% decline that mirrors the volume drop and rules out any technical artifact explanation. Kalshi, by contrast, captured 72.1% of combined weekly volume by early May, according to DeFi Rate.
Operational Stumbles Add Up
Polymarket’s April was a mess of its own making. A V2 upgrade on April 28 was supposed to take five minutes; the outage exceeded an hour and wiped all open orders. VP of engineering Josh Stevens admitted that “the rollout was terrible” on the platform’s Discord. A botched fee rollout drew similar internal criticism. Founder Shayne Coplan has publicly acknowledged the challenges that come with the company’s rapid growth, speaking at the MIT Sloan Sports Analytics Conference in March 2026.
The competitive gap now shows up in valuations. Kalshi raised $1B at a $22B valuation led by Coatue Management last month. Polymarket is reportedly only in talks to raise at a $15B valuation — a $7B gap that reflects more than just one bad month.
ICE CEO Jeff Sprecher, whose company committed up to $2B to Polymarket at escalating valuations, has reportedly grown impatient. Sprecher told Coplan that without US legal access, Polymarket would never become a prime-time company, per Bloomberg. The core problem: Polymarket’s international exchange runs on crypto rails, creating infrastructure complexity that Kalshi’s conventional approach simply doesn’t face.
FAQ
Why is Kalshi growing faster than Polymarket?
Kalshi’s growth is driven by sports contracts, which made up 74-85% of its weekly volume in April. The Masters alone drove $545M. Kalshi also doesn’t face the crypto-rails infrastructure complexity that has slowed Polymarket’s US product rollout.
Is Polymarket’s decline temporary?
The 12% drop in active traders suggests the volume decline is structural, not just a timing issue. Polymarket ended its US iOS waitlist in May — six months after first accepting bets — but the V2 upgrade problems and botched fee rollout indicate execution problems beyond product availability.
What about regulatory pressure?
Wisconsin’s attorney general filed lawsuits in April against both Polymarket and Kalshi, alleging violations of state sports betting laws. Senator Warren and 40+ members of Congress have also demanded the CFTC enforce existing insider trading prohibitions in prediction markets and provide government-wide guidance for federal employees.
[Editor’s note: This article was updated on May 17, 2026 to correct two claims. First, the description of the Warren/Congressional letter: original text stated the letter demanded the CFTC “ban government insiders from trading on prediction markets”; corrected to reflect that the letter asked the CFTC to enforce existing insider trading prohibitions and provide government-wide guidance, per the official letter from Senator Warren’s office. Second, Coplan’s venue and remarks: original text stated “Founder Shayne Coplan, speaking at Harvard, acknowledged that the company’s operations had at times been suboptimal”; corrected to note his confirmed appearance was at the MIT Sloan Sports Analytics Conference and his remarks concerned growth-related challenges, not operational suboptimality. No accessible source confirms a Harvard appearance or the word “suboptimal.”]
