2026 US midterm elections — Senate control
Republican Party controls the Senate. Listed on both Kalshi and Polymarket; recorded continuously since Aug 9, 2026. Live.
Current gap between the two mids: 1.0¢. Over the last 7 days the two venues differed by 2.6% on average and 5.4% at most.
Price history, both venues (7 days)
kalshipolymarket
Data table
| time (UTC) | kalshi mid | polymarket mid |
|---|---|---|
| Sep 18 10:20 | 41.5% | 41.5% |
| Sep 18 10:25 | 41.5% | 41.5% |
| Sep 18 10:30 | 41.5% | 41.5% |
| Sep 18 10:35 | 41.5% | 41.5% |
| Sep 18 10:40 | 41.5% | 41.5% |
| Sep 18 10:45 | 41.5% | 41.5% |
| Sep 18 10:50 | 41.5% | 41.5% |
| Sep 18 10:55 | 41.5% | 41.5% |
| Sep 18 11:00 | 41.5% | 41.5% |
| Sep 18 11:05 | 41.5% | 41.5% |
| Sep 18 11:10 | 41.5% | 41.5% |
| Sep 18 11:15 | 41.5% | 41.5% |
| Sep 18 11:20 | 41.5% | 41.5% |
| Sep 18 11:25 | 41.5% | 41.5% |
| Sep 18 11:30 | 41.5% | 41.5% |
| Sep 18 11:35 | 41.5% | 41.5% |
| Sep 18 11:40 | 41.8% | 40.5% |
| Sep 18 11:45 | 42.5% | 40.5% |
| Sep 18 11:50 | 41.9% | 40.5% |
| Sep 18 11:55 | 41.5% | 40.5% |
| Sep 18 12:00 | 41.5% | 40.5% |
| Sep 18 12:05 | 41.5% | 40.5% |
| Sep 18 12:10 | 41.5% | 40.5% |
| Sep 18 12:15 | 41.5% | 40.5% |
| Sep 18 12:20 | 41.5% | 40.5% |
| Sep 18 12:25 | 41.5% | 40.5% |
| Sep 18 12:30 | 41.5% | 40.5% |
| Sep 18 12:35 | 41.5% | 40.5% |
| Sep 18 12:40 | 41.5% | 40.5% |
| Sep 18 12:45 | 41.5% | 40.5% |
| Sep 18 12:50 | 41.5% | 40.5% |
| Sep 18 12:55 | 41.5% | 40.5% |
| Sep 18 13:00 | 41.5% | 40.5% |
| Sep 18 13:05 | 41.5% | 40.5% |
| Sep 18 13:10 | 41.5% | 40.5% |
| Sep 18 13:15 | 41.5% | 40.5% |
| Sep 18 13:20 | 41.5% | 40.5% |
| Sep 18 13:25 | 41.5% | 40.5% |
| Sep 18 13:30 | 41.5% | 40.5% |
| Sep 18 13:35 | 41.5% | 40.5% |
| Sep 18 13:40 | 41.5% | 40.5% |
| Sep 18 13:45 | 41.5% | 40.5% |
| Sep 18 13:50 | 41.5% | 40.5% |
| Sep 18 13:55 | 41.5% | 40.5% |
| Sep 18 14:00 | 41.5% | 40.5% |
| Sep 18 14:05 | 41.5% | 40.5% |
| Sep 18 14:10 | 41.5% | 40.5% |
| Sep 18 14:15 | 41.5% | 40.5% |
| Sep 18 14:20 | 41.5% | 40.5% |
| Sep 18 14:25 | 41.5% | 40.5% |
| Sep 18 14:30 | 41.5% | — |
| Sep 18 14:35 | 41.5% | — |
| Sep 18 14:40 | 41.5% | — |
| Sep 18 14:45 | 41.5% | — |
| Sep 18 14:50 | 41.5% | — |
| Sep 18 14:55 | 41.5% | — |
| Sep 18 15:00 | 41.5% | — |
| Sep 18 15:05 | 41.5% | — |
| Sep 18 15:10 | 41.3% | — |
| Sep 18 15:15 | 40.5% | — |
| Sep 18 15:20 | 40.5% | — |
| Sep 18 15:25 | 40.5% | — |
| Sep 18 15:30 | 40.5% | — |
| Sep 18 15:35 | 40.5% | — |
| Sep 18 15:40 | 40.5% | — |
| Sep 18 15:45 | 40.5% | — |
| Sep 18 15:50 | 40.5% | — |
| Sep 18 15:55 | 40.5% | — |
| Sep 18 16:00 | 40.5% | — |
| Sep 18 16:05 | 40.5% | — |
| Sep 18 16:10 | 40.5% | — |
| Sep 18 16:15 | 40.5% | — |
| Sep 18 16:20 | 40.5% | — |
| Sep 18 16:25 | 40.5% | — |
| Sep 18 16:30 | 40.5% | — |
| Sep 18 16:35 | 40.5% | — |
| Sep 18 16:40 | 40.5% | — |
| Sep 18 16:45 | 40.5% | — |
| Sep 18 16:50 | 40.5% | — |
| Sep 18 16:55 | 40.5% | — |
| Sep 18 17:00 | 40.5% | — |
| Sep 18 17:05 | 40.5% | — |
| Sep 18 17:10 | 40.5% | — |
| Sep 18 17:15 | 40.5% | — |
| Sep 18 17:20 | 40.5% | — |
| Sep 18 17:25 | 40.5% | — |
| Sep 18 17:30 | 40.5% | — |
| Sep 18 17:35 | 40.5% | — |
| Sep 18 17:40 | 40.5% | — |
| Sep 18 17:45 | 40.5% | — |
| Sep 18 17:50 | 40.5% | — |
| Sep 18 17:55 | 40.5% | — |
| Sep 18 18:00 | 40.5% | — |
| Sep 18 18:05 | 40.5% | — |
| Sep 18 18:10 | 40.5% | — |
| Sep 18 18:15 | 40.5% | — |
| Sep 18 18:20 | 40.5% | — |
| Sep 18 18:25 | 40.5% | — |
| Sep 18 18:30 | 40.5% | — |
| Sep 18 18:35 | 40.5% | — |
| Sep 18 18:40 | 40.5% | — |
| Sep 18 18:45 | 40.5% | — |
| Sep 18 18:50 | 40.5% | — |
| Sep 18 18:55 | 40.5% | — |
| Sep 18 19:00 | 40.5% | — |
| Sep 18 19:05 | 40.5% | — |
| Sep 18 19:10 | 40.5% | — |
| Sep 18 19:15 | 40.5% | — |
| Sep 18 19:20 | 40.5% | — |
| Sep 18 19:25 | 40.5% | — |
| Sep 18 19:30 | 40.5% | — |
| Sep 18 19:35 | 40.5% | — |
| Sep 18 19:40 | 40.5% | — |
| Sep 18 19:45 | 40.5% | — |
| Sep 18 19:50 | 40.5% | — |
| Sep 18 19:55 | 40.5% | — |
| Sep 18 20:00 | 40.5% | — |
| Sep 18 20:05 | 40.5% | — |
| Sep 18 20:10 | 40.5% | — |
| Sep 18 20:15 | 40.5% | — |
| Sep 18 20:20 | 40.5% | — |
| Sep 18 20:25 | 40.5% | — |
| Sep 18 20:30 | 40.5% | — |
| Sep 18 20:35 | 40.5% | — |
| Sep 18 20:40 | 40.5% | — |
| Sep 18 20:45 | 40.5% | — |
| Sep 18 20:50 | 40.5% | — |
| Sep 18 20:55 | 40.5% | — |
| Sep 18 21:00 | 40.5% | — |
| Sep 18 21:05 | 40.5% | — |
| Sep 18 21:10 | 40.5% | — |
| Sep 18 21:15 | 40.5% | — |
| Sep 18 21:20 | 40.5% | — |
| Sep 18 21:25 | 40.5% | — |
| Sep 18 21:30 | 40.5% | — |
| Sep 18 21:35 | 40.5% | — |
| Sep 18 21:40 | 40.5% | — |
| Sep 18 21:45 | 40.5% | — |
| Sep 18 21:50 | 40.5% | — |
| Sep 18 21:55 | 40.5% | — |
| Sep 18 22:00 | 40.5% | — |
| Sep 18 22:05 | 40.5% | — |
| Sep 18 22:10 | 40.5% | — |
| Sep 18 22:15 | 40.5% | — |
| Sep 18 22:20 | 40.5% | — |
| Sep 18 22:25 | 40.5% | — |
| Sep 18 22:30 | 40.5% | — |
| Sep 18 22:35 | 40.5% | — |
| Sep 18 22:40 | 40.5% | — |
| Sep 18 22:45 | 40.5% | — |
| Sep 18 22:50 | 40.5% | — |
| Sep 18 22:55 | 40.5% | — |
| Sep 18 23:00 | 40.5% | — |
| Sep 18 23:05 | 40.5% | — |
| Sep 18 23:10 | 40.5% | — |
| Sep 18 23:15 | 40.5% | — |
| Sep 18 23:20 | 40.5% | — |
| Sep 18 23:25 | 40.5% | — |
| Sep 18 23:30 | 40.5% | — |
| Sep 18 23:35 | 40.5% | — |
| Sep 18 23:40 | 40.5% | — |
| Sep 18 23:45 | 40.5% | — |
| Sep 18 23:50 | 40.5% | — |
| Sep 18 23:55 | 40.5% | — |
| Sep 19 00:00 | 40.5% | — |
| Sep 19 00:05 | 40.5% | — |
| Sep 19 00:10 | 40.5% | — |
| Sep 19 00:15 | 40.5% | — |
| Sep 19 00:20 | 40.5% | — |
| Sep 19 00:25 | 40.5% | — |
| Sep 19 00:30 | 40.5% | — |
| Sep 19 00:35 | 40.5% | — |
| Sep 19 00:40 | 40.5% | — |
| Sep 19 00:45 | 40.5% | — |
| Sep 19 00:50 | 40.5% | — |
| Sep 19 00:55 | 40.5% | — |
| Sep 19 01:00 | 41.0% | — |
| Sep 19 01:05 | 41.5% | — |
| Sep 19 01:10 | 41.5% | — |
| Sep 19 01:15 | 41.5% | — |
| Sep 19 01:20 | 41.5% | — |
| Sep 19 01:25 | 41.5% | — |
| Sep 19 01:30 | 41.4% | — |
| Sep 19 01:35 | 41.5% | — |
| Sep 19 01:40 | 41.5% | — |
| Sep 19 01:45 | 41.5% | — |
| Sep 19 01:50 | 41.5% | — |
| Sep 19 01:55 | 41.5% | — |
| Sep 19 02:00 | 41.5% | — |
| Sep 19 02:05 | 41.5% | — |
| Sep 19 02:10 | 41.5% | — |
| Sep 19 02:15 | 41.5% | — |
| Sep 19 02:20 | 41.5% | — |
| Sep 19 02:25 | 41.5% | — |
| Sep 19 02:30 | 41.5% | — |
| Sep 19 02:35 | 41.5% | — |
| Sep 19 02:40 | 41.5% | — |
| Sep 19 02:45 | 41.5% | — |
| Sep 19 02:50 | 41.5% | — |
| Sep 19 02:55 | 41.5% | — |
| Sep 19 03:00 | 41.5% | — |
| Sep 19 03:05 | 41.5% | — |
| Sep 19 03:10 | 41.5% | — |
| Sep 19 03:15 | 41.5% | — |
| Sep 19 03:20 | 41.5% | — |
| Sep 19 03:25 | 41.5% | — |
| Sep 19 03:30 | 41.5% | — |
| Sep 19 03:35 | 41.5% | — |
| Sep 19 03:40 | 41.5% | — |
| Sep 19 03:45 | 41.5% | — |
| Sep 19 03:50 | 41.5% | — |
| Sep 19 03:55 | 41.5% | — |
| Sep 19 04:00 | 41.5% | — |
| Sep 19 04:05 | 41.5% | — |
| Sep 19 04:10 | 41.5% | — |
| Sep 19 04:15 | 41.5% | — |
| Sep 19 04:20 | 41.5% | — |
| Sep 19 04:25 | 41.5% | — |
| Sep 19 04:30 | 41.5% | — |
| Sep 19 04:35 | 41.5% | — |
| Sep 19 04:40 | 41.5% | — |
| Sep 19 04:45 | 41.5% | — |
| Sep 19 04:50 | 41.5% | — |
| Sep 19 04:55 | 41.5% | — |
| Sep 19 05:00 | 41.5% | — |
| Sep 19 05:05 | 41.5% | — |
| Sep 19 05:10 | 41.5% | — |
| Sep 19 05:15 | 41.5% | — |
| Sep 19 05:20 | 41.5% | — |
| Sep 19 05:25 | 41.5% | — |
| Sep 19 05:30 | 41.5% | — |
| Sep 19 05:35 | 41.5% | — |
| Sep 19 05:40 | 41.5% | — |
| Sep 19 05:45 | 41.5% | — |
| Sep 19 05:50 | 41.5% | — |
| Sep 19 05:55 | 41.5% | — |
| Sep 19 06:00 | 41.5% | — |
| Sep 19 06:05 | 41.5% | — |
| Sep 19 06:10 | 41.5% | — |
| Sep 19 06:15 | 41.5% | — |
| Sep 19 06:20 | 41.5% | — |
| Sep 19 06:25 | 41.5% | — |
| Sep 19 06:30 | 41.5% | — |
| Sep 19 06:35 | 41.5% | — |
| Sep 19 06:40 | 41.5% | — |
| Sep 19 06:45 | 41.5% | — |
| Sep 19 06:50 | 41.5% | — |
| Sep 19 06:55 | 41.5% | — |
| Sep 19 07:00 | 41.5% | — |
| Sep 19 07:05 | 41.5% | — |
| Sep 19 07:10 | 41.5% | — |
| Sep 19 07:15 | 41.5% | — |
| Sep 19 07:20 | 41.5% | — |
| Sep 19 07:25 | 41.5% | — |
| Sep 19 07:30 | 41.5% | — |
| Sep 19 07:35 | 41.5% | — |
| Sep 19 07:40 | 41.5% | — |
| Sep 19 07:45 | 41.5% | — |
| Sep 19 07:50 | 41.5% | — |
| Sep 19 07:55 | 41.5% | — |
| Sep 19 08:00 | 41.5% | — |
| Sep 19 08:05 | 41.5% | — |
| Sep 19 08:10 | 41.5% | — |
| Sep 19 08:15 | 41.5% | — |
| Sep 19 08:20 | 41.5% | — |
| Sep 19 08:25 | 41.5% | — |
| Sep 19 08:30 | 41.5% | — |
| Sep 19 08:35 | 41.5% | — |
| Sep 19 08:40 | 41.5% | — |
| Sep 19 08:45 | 41.5% | — |
| Sep 19 08:50 | 41.5% | — |
| Sep 19 08:55 | 41.5% | — |
| Sep 19 09:00 | 41.5% | — |
| Sep 19 09:05 | 41.5% | — |
| Sep 19 09:10 | 41.5% | — |
| Sep 19 09:15 | 41.5% | — |
| Sep 19 09:20 | 41.5% | — |
| Sep 19 09:25 | 41.5% | — |
| Sep 19 09:30 | 41.5% | — |
| Sep 19 09:35 | 41.5% | — |
| Sep 19 09:40 | 41.5% | — |
| Sep 19 09:45 | 41.5% | — |
Mid price of the YES side per venue, 5-minute buckets, from continuously recorded order books. Breaks mean the recorder was down or a book was empty.
Disagreement windows
24
beyond fees, at size
Largest net edge
1.27%
avg 0.33%
Typical window
623 min
longest 2955 min
Last window
Sep 17, 2026
first Aug 17, 2026
Recent disagreement windows
| Opened | Closed | Length | Scans | Max net edge |
|---|---|---|---|---|
| Sep 17, 5:00 AM ET | Sep 17, 9:38 AM ET | 4.6 h | 471 | 0.31% |
| Sep 16, 7:53 PM ET | Sep 17, 4:18 AM ET | 8.4 h | 212 | 0.45% |
| Sep 15, 1:13 PM ET | Sep 15, 8:45 PM ET | 7.5 h | 221 | 1.24% |
| Sep 14, 7:04 AM ET | Sep 14, 10:12 AM ET | 3.1 h | 28 | 0.25% |
| Sep 13, 8:03 AM ET | Sep 14, 6:27 AM ET | 22.4 h | 326 | 1.27% |
| Sep 12, 5:24 PM ET | Sep 13, 7:22 AM ET | 14.0 h | 127 | 0.25% |
| Sep 12, 10:20 AM ET | Sep 12, 10:20 AM ET | 0 min | 1 | 0.25% |
| Sep 10, 9:52 AM ET | Sep 11, 1:33 PM ET | 27.7 h | 291 | 0.25% |
| Sep 10, 7:27 AM ET | Sep 10, 9:21 AM ET | 1.9 h | 29 | 0.25% |
| Sep 10, 6:06 AM ET | Sep 10, 6:44 AM ET | 39 min | 4 | 0.25% |
Frequently asked questions
What are the current Kalshi and Polymarket odds for "2026 US midterm elections — Senate control"?
As of the latest recorded books, Kalshi's YES mid is 41.5¢ (bid 0.41, ask 0.42) and Polymarket's is 40.5¢ (bid 0.4, ask 0.41) — a 1.0¢ gap. Prices are recorded continuously; this page refreshes every few minutes.
Has this market been an arbitrage?
Yes — 24 separate windows where buying the cheaper side on each venue cost less than $1 after both fees, first on Aug 17, 2026 and most recently Sep 17, 2026. The largest net edge was 1.27% and windows averaged 623 minutes.
Do both contracts resolve the same way?
The pair was confirmed as the same question (human-reviewed). That judgment covers the headline question; resolution rules can still differ in edge cases (sources, timing, ties). Read both venues' rules before treating a gap as risk-free.
What do the fees do to the gap?
Kalshi charges takers 7% × price × (1 − price) per contract; Polymarket charges its category rate on the same curve. Near 50¢ that is roughly 1.75¢ per contract on Kalshi and 1–1.75¢ on Polymarket, so a visible gap of 3–4¢ is typically the minimum before anything is left.
← every Kalshi↔Polymarket pair · resolution criteria · taker fees · match: human-reviewed. Verify both markets' rules yourself; this is data, not advice.