Prediction market volume continues to climb heading into the final stretch of 2026, with the combined weekly notional on Kalshi and Polymarket crossing the half-billion-dollar mark for the fifth consecutive week. This week’s rankings are driven by three themes: the Federal Reserve’s late-October policy signal, intensifying 2026 midterm positioning, and a sharp spike in crypto-price contracts tied to Bitcoin’s push above $120,000.
Below is PredictWire’s volume-weighted ranking of the top-moving contracts across the two leading US-accessible prediction markets, with current implied probabilities and the direction of travel over the past seven days.
Top 10 Volume Leaders This Week
| Rank | Contract | Platform | Current Odds | 7-Day Move |
|---|---|---|---|---|
| 1 | Will the Fed cut rates at the October 29 meeting? | Kalshi | 71% | +9 pts |
| 2 | Will Republicans hold the US Senate in 2026? | Polymarket | 54% | -3 pts |
| 3 | Bitcoin above $130,000 by December 31, 2026? | Polymarket | 38% | +12 pts |
| 4 | Will US CPI print below 2.5% in October? | Kalshi | 62% | +4 pts |
| 5 | Will Democrats flip the US House in 2026? | Polymarket | 47% | +2 pts |
| 6 | Will Ethereum close above $5,000 in October? | Polymarket | 44% | +8 pts |
| 7 | Will the S&P 500 finish 2026 above 6,500? | Kalshi | 58% | +5 pts |
| 8 | Will OpenAI announce GPT-6 before year-end? | Polymarket | 29% | -6 pts |
| 9 | Will the US enter a recession in Q4 2026? | Kalshi | 18% | -4 pts |
| 10 | Will Taylor Swift and Travis Kelce marry in 2026? | Polymarket | 22% | +3 pts |
Fed Decision Dominates the Tape
The clear volume leader this week is Kalshi’s October FOMC contract, where traders have poured more than $42 million into the “rate cut” side since Monday. The implied probability of a 25 basis point cut on October 29 jumped from 62% to 71% after softer-than-expected September payrolls and dovish commentary from two regional Fed presidents. The move is consistent with Fed funds futures, which are pricing a cut at roughly 73%, giving arbitrage-minded traders a narrow but real spread to exploit.
The parallel Polymarket contract on the same event is trading slightly tighter at 69%, creating a small cross-platform divergence that quant desks have been actively closing.
Midterm Positioning Heats Up
With three weeks until Election Day, political contracts account for roughly 31% of weekly volume across both platforms. The Senate control contract on Polymarket has been the biggest political mover, with Republican odds slipping from 57% to 54% as polling tightens in Pennsylvania, Ohio, and Arizona. The House contract remains a near coin flip at 47% Democratic, with the forecast model implied by current market prices suggesting a 3- to 7-seat swing is the most likely outcome.
Governor races are quieter, but Kalshi’s state-by-state contracts have seen their open interest double since early October as retail traders discover the market.
Crypto Contracts Surge on Bitcoin Breakout
Bitcoin’s push to new all-time highs above $122,000 has pulled crypto prediction contracts into the top ten for the first time since July. Polymarket’s “BTC above $130K by year-end” market has become the fastest-growing contract on the platform, with volume up 240% week-over-week and the probability climbing from 26% to 38%.
Ethereum contracts followed the leader, with the “ETH above $5,000 in October” market rallying 8 points to 44%. Traders should note that both contracts settle at the end-of-month close on major reference exchanges, meaning late-month volatility can dramatically reprice these markets in the final 48 hours.
Notable Faders and Contrarian Plays
Not every market is rising. The GPT-6 announcement contract on Polymarket has drifted lower all week, from 35% to 29%, as traders digest reporting that OpenAI’s next frontier model may slip into Q1 2027. Recession-odds contracts have also faded, dropping to 18% as September data came in firmer than feared. Contrarians argue the 18% level is now too low given still-inverted parts of the yield curve, and there has been notable buying of the “yes” side from a handful of larger wallets on Kalshi.
Where to Trade These Markets
If you want to take a position in any of this week’s top contracts, the two venues doing the overwhelming majority of US-accessible volume are:
- Kalshi: CFTC-regulated, best for economic, political, and macro contracts. Deepest liquidity on Fed and CPI markets.
- Polymarket: The volume leader for crypto, culture, and global political contracts. Settles in USDC.
For a full breakdown of fees, deposit methods, and state eligibility across every major platform, see our constantly updated rankings of the best prediction markets.
PredictWire will publish the next weekly rankings update next Tuesday. In the meantime, watch the October 29 FOMC contract: with a week to go, every incoming data point will reprice it, and the cross-platform spread between Kalshi and Polymarket remains the cleanest arbitrage on the board.