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Middleweight Title Holder on Dec 31, 2026? Nassourdine Imavov

Nassourdine Imavov is the official UFC Middleweight Champion at 12:00 PM ET on December 31, 2026. Listed on both Kalshi and Polymarket; recorded continuously since Aug 17, 2026. Live.

kalshi
34.0¢
bid 0.33 · ask 0.35 · Sep 19, 6:03 AM ET
polymarket
35.7¢
bid 0.347 · ask 0.368 · Sep 19, 5:57 AM ET

Current gap between the two mids: 1.7¢. Over the last 7 days the two venues differed by 2.1% on average and 5.4% at most.

Price history, both venues (7 days)

kalshipolymarket
31.9%33.2%34.5%35.8%37.2%10:2018:1302:0610:00kalshipolymarket
Data table
time (UTC)kalshi midpolymarket mid
Sep 18 10:2035.8%36.5%
Sep 18 10:2535.6%36.3%
Sep 18 10:3035.9%36.3%
Sep 18 10:3536.0%36.3%
Sep 18 10:4035.6%36.3%
Sep 18 10:4536.0%36.3%
Sep 18 10:5035.8%35.7%
Sep 18 10:5536.0%35.6%
Sep 18 11:0036.0%35.7%
Sep 18 11:0535.8%35.8%
Sep 18 11:1035.9%
Sep 18 11:1536.0%
Sep 18 11:4034.5%
Sep 18 12:2034.5%
Sep 18 12:3034.5%
Sep 18 13:0534.0%
Sep 18 13:2035.5%
Sep 18 13:2535.5%
Sep 18 13:3534.3%
Sep 18 13:4034.0%
Sep 18 13:4534.5%
Sep 18 13:5534.5%
Sep 18 14:1034.5%
Sep 18 14:3534.5%
Sep 18 15:1035.5%
Sep 18 15:1535.3%
Sep 18 15:2035.5%
Sep 18 15:2535.5%
Sep 18 15:3035.5%
Sep 18 15:3535.4%
Sep 18 15:4035.4%
Sep 18 15:4534.9%
Sep 18 15:5035.1%
Sep 18 15:5535.1%
Sep 18 16:0034.9%
Sep 18 16:0535.5%
Sep 18 16:1035.3%
Sep 18 16:1535.5%
Sep 18 16:2035.1%
Sep 18 16:2535.5%
Sep 18 16:3035.5%
Sep 18 16:3535.4%
Sep 18 16:4035.5%
Sep 18 16:4535.4%
Sep 18 16:5035.5%
Sep 18 16:5535.4%
Sep 18 17:0035.5%
Sep 18 17:0535.4%
Sep 18 17:1035.4%
Sep 18 17:1535.5%
Sep 18 17:2035.4%
Sep 18 17:2535.5%
Sep 18 17:3035.5%
Sep 18 17:3535.5%
Sep 18 17:4035.4%
Sep 18 17:4535.5%
Sep 18 17:5035.4%
Sep 18 17:5535.5%
Sep 18 18:0035.4%
Sep 18 18:0535.4%
Sep 18 18:1035.3%
Sep 18 18:2034.0%
Sep 18 18:5034.5%
Sep 18 18:5534.5%
Sep 18 20:3534.5%
Sep 18 20:5034.0%
Sep 18 21:1034.0%
Sep 18 21:1534.4%
Sep 18 21:2033.2%
Sep 18 21:2533.0%
Sep 18 21:3034.0%
Sep 18 21:3533.3%
Sep 18 21:4534.5%
Sep 18 21:5035.3%
Sep 18 22:2035.5%
Sep 18 22:2535.5%
Sep 18 22:3035.5%
Sep 18 22:4035.5%
Sep 18 22:5035.5%
Sep 18 22:5533.3%
Sep 18 23:1033.5%
Sep 18 23:2033.5%
Sep 18 23:2533.5%
Sep 18 23:5533.5%
Sep 19 00:0033.5%
Sep 19 00:0533.5%
Sep 19 00:1533.5%
Sep 19 00:2033.5%
Sep 19 00:2533.0%
Sep 19 00:3033.0%
Sep 19 00:3533.0%
Sep 19 00:4033.0%
Sep 19 00:5033.2%
Sep 19 01:0033.5%
Sep 19 01:0533.5%
Sep 19 01:1033.5%
Sep 19 01:2035.0%
Sep 19 01:2535.0%
Sep 19 01:4534.5%
Sep 19 01:5035.5%
Sep 19 02:0535.5%
Sep 19 02:1035.5%
Sep 19 02:1535.5%
Sep 19 02:2035.5%
Sep 19 02:2534.9%
Sep 19 02:3034.5%
Sep 19 02:3534.4%
Sep 19 02:4034.5%
Sep 19 02:4534.5%
Sep 19 02:5034.5%
Sep 19 03:0034.5%
Sep 19 03:0534.5%
Sep 19 03:1034.5%
Sep 19 03:1534.5%
Sep 19 03:2034.5%
Sep 19 03:2534.5%
Sep 19 03:3034.5%
Sep 19 03:3534.1%
Sep 19 03:4033.9%
Sep 19 03:4533.9%
Sep 19 03:5034.0%
Sep 19 03:5533.9%
Sep 19 04:0033.6%
Sep 19 04:0534.0%
Sep 19 04:1033.8%
Sep 19 04:1534.5%
Sep 19 04:2034.5%
Sep 19 04:2534.0%
Sep 19 05:1033.3%
Sep 19 05:1533.5%
Sep 19 05:2033.3%
Sep 19 05:3033.3%
Sep 19 05:4033.3%
Sep 19 05:4533.5%
Sep 19 05:5034.0%
Sep 19 05:5533.9%
Sep 19 06:0033.3%
Sep 19 06:1033.5%
Sep 19 06:1533.0%
Sep 19 06:2533.0%
Sep 19 06:3533.3%
Sep 19 06:4533.0%
Sep 19 06:5533.0%
Sep 19 07:0533.0%
Sep 19 07:1033.5%
Sep 19 07:1534.0%
Sep 19 07:2033.5%
Sep 19 07:2533.3%
Sep 19 07:3033.5%
Sep 19 07:3533.5%
Sep 19 07:4034.0%
Sep 19 07:4532.5%
Sep 19 07:5033.9%
Sep 19 07:5533.3%
Sep 19 08:0033.9%
Sep 19 08:0533.7%
Sep 19 08:1033.5%
Sep 19 08:1533.5%
Sep 19 08:2033.5%
Sep 19 08:2533.5%
Sep 19 08:3033.5%
Sep 19 08:3533.5%
Sep 19 08:4033.5%
Sep 19 08:4533.5%
Sep 19 08:5033.5%
Sep 19 08:5533.5%
Sep 19 09:0033.5%
Sep 19 09:0533.5%
Sep 19 09:1033.5%
Sep 19 09:1533.5%
Sep 19 09:2033.5%
Sep 19 09:2533.8%
Sep 19 09:3034.0%
Sep 19 09:3534.0%
Sep 19 09:4034.0%
Sep 19 09:4534.0%
Sep 19 09:5034.0%
Sep 19 09:5534.0%
Sep 19 10:0034.0%

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
10
beyond fees, at size
Largest net edge
2.32%
avg 1.01%
Typical window
435 min
longest 2674 min
Last window
Sep 14, 2026
first Aug 17, 2026

Recent disagreement windows

OpenedClosedLengthScansMax net edge
Sep 14, 4:42 AM ETSep 14, 4:49 AM ET7 min20.41%
Sep 14, 1:35 AM ETSep 14, 4:02 AM ET2.5 h1130.55%
Sep 13, 9:27 PM ETSep 14, 1:01 AM ET3.6 h840.83%
Sep 13, 7:47 PM ETSep 13, 8:16 PM ET29 min60.54%
Aug 26, 1:37 PM ETAug 28, 10:11 AM ET44.6 h6391.68%
Aug 26, 11:13 AM ETAug 26, 11:16 AM ET3 min20.54%
Aug 26, 9:54 AM ETAug 26, 9:57 AM ET3 min20.23%
Aug 25, 5:15 AM ETAug 25, 8:12 PM ET15.0 h2481.22%
Aug 18, 4:04 PM ETAug 18, 5:18 PM ET74 min50.99%
Aug 17, 7:07 PM ETAug 18, 12:10 AM ET5.0 h2082.32%

Frequently asked questions

What are the current Kalshi and Polymarket odds for "Middleweight Title Holder on Dec 31, 2026? Nassourdine Imavov"?

As of the latest recorded books, Kalshi's YES mid is 34.0¢ (bid 0.33, ask 0.35) and Polymarket's is 35.7¢ (bid 0.347, ask 0.368) — a 1.7¢ gap. Prices are recorded continuously; this page refreshes every few minutes.

Has this market been an arbitrage?

Yes — 10 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 14, 2026. The largest net edge was 2.32% and windows averaged 435 minutes.

Do both contracts resolve the same way?

The pair was confirmed as the same question (AI-matched · 100%). 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: AI-matched · 100%. Verify both markets' rules yourself; this is data, not advice.