Two Prediction Markets Shut Down Hours Apart as Kalshi and Polymarket Take 93% of Volume

Two crypto prediction market startups announced they were winding down within 90 minutes of each other on Monday morning, both giving users until Sept. 30 to pull their money out.

The venues that closed sat at opposite ends of the market. Trepa built its own mechanism on Solana, paying users by how close their numerical guess landed to an outcome. Fireplace built a professional trading terminal on top of Polymarket and charged a fee for routing orders there. Neither found a position that survived contact with the two exchanges that now absorb nearly all the trading.

Kalshi and Polymarket took 93.3% of the past 30 days' volume across the 40 prediction market venues DefiLlama tracks with volume adapters — $13.87 billion of $14.87 billion. Kalshi alone accounted for 75.7%. The third-largest venue, BNB Chain-based OPINION, took 2.8%. Kalshi has raised $2.685 billion and was last valued at $22 billion; Intercontinental Exchange has put $1.6 billion into Polymarket across two tranches. Trepa raised $420,000. Fireplace raised $1.5 million.

The Concurrency Trap

Trepa's founders, who signed the announcement as Jong and Leon, published roughly 1,200 words on what went wrong. The company raised its pre-seed in August 2025 led by Colosseum, with participation from Ignight Capital and angels including Balaji Srinivasan, and launched on Solana mainnet on Dec. 8, 2025. Its last playable round is Aug. 12.

The product paid out pari-mutuel, splitting a pool by how close each entrant's number came to the result, which meant it needed a crowd predicting inside the same window. Trepa ran one live hour a day, from 1 to 2 p.m. UTC, in 60-second rounds on bitcoin's price.

"Retention degraded under that ask, and degraded more the longer someone had been with us," the founders wrote. Expanding to more assets and more time windows would have thinned the pools the mechanism depended on: "In the end we could not see a version of scaling Trepa that did not first make Trepa worse."

Distribution failed on both channels the team tried. "Referrals did not work and paid KOLs returned almost nothing," they wrote. Partner conversations about embedding Trepa's widget kept returning to the single daily hour, which existed because the mechanism needed concurrency — "Explaining your structural weakness as part of the pitch is not a strong position."

Hundreds Of Thousands, Not Millions

The claim with the widest reach past Trepa's own balance sheet concerns the size of the market everyone else is also selling into.

"Reported crypto DAU and MAU figures, including from sources we trusted, are softer than they look," the founders wrote. "Our working conclusion is that the genuinely active audience for a product like this is in the hundreds of thousands at the moment, not the millions."

They also named geographic restrictions, which "removed a large share of the addressable audience before we started," and onramping. Their conclusion on the mechanic itself: "in consumer betting, simplicity may be the whole product."

Retail returns give that assessment support. Research covering 2.5 million wallets found 84% of Polymarket traders are losing money, with only 2% ever clearing $1,000 in profit.

One Percent On Top

Fireplace, operated by Hong Kong-registered Enclave HK Limited and founded by Sumer Malhotra and Akshay Rajagopal, gave no reason for closing. "It was a hell of a run," the team wrote, adding that anyone building in prediction markets should get in touch about the technology.

The company aggregated third-party venues rather than running its own book. Its terms of use name Kalshi and Polymarket as execution destinations, though its fee schedule references only Polymarket, charging a 1% taker fee "in addition to any fees levied by Polymarket." The wind-down page now routes departing users to Polymarket directly: "Fireplace runs on the same Polymarket markets, so your positions carry over."

Fireplace launched publicly on Jan. 27, 2026 and announced its pre-seed on Feb. 17, led by Frachtis with White Star Capital and angels including Wintermute co-founder Evgeny Gaevoy. At the time it reported a waitlist above 30,000. Six months later Kalshi released Kalshi Pro on July 13, a free desktop terminal with a screener across roughly 2,000 markets and an integrated perpetuals interface — the same category Fireplace occupied, from the venue holding three quarters of the volume.

The front-end layer was crowded before that. DefiLlama tracks more than 20 interface wrappers routing to Polymarket, including Gate Predictions at $48.3 million in 30-day volume and Traderline at $61.3 million.

The backdrop is a bitcoin price of $64,977, down 48.5% from its all-time high of $126,080 on Oct. 6, 2025, according to CoinGecko. Capital has not left the category: ProphetX raised $35 million on July 28 and Pascal raised a $9 million Series A on July 16, both aimed at the regulated US market rather than at building a differentiated onchain mechanism.

Trepa's founders did not disown the idea. "We still think there is something in the argument that people will pay to be measured on how close they get," they wrote. "We were not the team that found the way to build a business around it."