What is the Duma market with $26.8 million traded on it actually pricing: which party wins Russia's 18 to 20 September election, or which party walks out with more seats than it walked in with? The rules settle that in their first line, and it is the second. Polymarket's Which party will gain most seats in Russian Parliamentary Election? event resolves to "the political party that gains the greatest number of seats in the next Russian State Duma election, compared to before the election." Links to Polymarket are affiliate links, from which The Traders Spread may earn a commission at no cost to you. Who wins is a separate contract and a closed question, with United Russia at 99.15% in Polymarket's winner market. This one is a subtraction. United Russia trades at 78%, New People at 17.85% and the LDPR at 3.05%, and nobody has said what the subtraction starts from.
That starting number is the trade. The State Duma's own website lists United Russia's faction at 310 members this morning, with 16 seats vacant; the party won 324 in 2021. Polymarket's United Russia seat-count market, a separate book with $550,116 traded, puts about 78% on the party finishing with 321 seats or more, reading its 310–324 bracket in a straight line, and 321 is roughly where it out-gains New People if you count from 310. That is the price, almost to the point. Count from 324 instead and the same seat market gives United Russia about a 42% chance of clearing the equivalent bar of 337. At 78%, the book is treating the most generous reading of the rule as settled and the rivals' gains as known. Neither is true.
- United Russia trades at 78.0% to gain the most seats, New People at 17.85%, the LDPR at 3.05% and the KPRF at 1.15%; the eight live legs sum to 100.45% — Polymarket gamma-api, 11 September 2026, 07:10 UTC
- The event has traded $26.76 million in total and $407,645 in the past 24 hours; the United Russia leg alone accounts for $9.66 million — Polymarket gamma-api, 11 September 2026
- United Russia's faction in the outgoing Duma numbers 310, with 16 mandates vacant and four deputies outside any faction — duma.gov.ru faction page, retrieved 11 September 2026
- United Russia won 324 seats in 2021, the KPRF 57, A Just Russia 27, the LDPR 21 and New People 13 — CEC chair Ella Pamfilova via RIA Novosti, 24 September 2021
- VTsIOM forecasts United Russia at 51–53% of the list vote, the KPRF at 13–15%, New People and the LDPR at 9–11% each, and A Just Russia at 4–6% — VTsIOM, 10 September 2026
- FOM forecasts United Russia at 47–49%, the KPRF at 14–17%, the LDPR at 10–12% and New People at 8–9% — FOM, 10 September 2026 (fieldwork 4–6 September, n=1,500)
- The seat-count market prices 72.5% on United Russia winning 325 seats or more — Polymarket gamma-api, 11 September 2026
Three numbers for one word: "before"
The resolution text is short. After the opening sentence it adds that the market "will resolve based solely on the number of seats gained by the named party in the State Duma", and it names its sources in order: first "a consensus of credible reporting", and only "if there is ambiguity" the official results from Russian government sources such as the Central Election Commission.
That hierarchy has a hole in it. The CEC does not publish a gains column. It publishes seat totals. When Ella Pamfilova, chair of the Central Election Commission, announced the final 2021 distribution, she said: "United Russia received 324 mandates, the KPRF 57, A Just Russia – For Truth 27, the LDPR 21 and New People 13" (RIA Novosti, 24 September 2021, translated from the Russian). Any "gain" has to be computed by someone, from a baseline someone picks.
There are at least three on the public record. The 2021 result is 324. The Moscow Times, in its 2 July 2026 election explainer, described United Russia as holding 321 of 450 seats. The Duma's faction page shows 310 today. The fourteen seats between the highest and lowest of those figures are larger than New People's median gain in our model.
The literal words favour 310. "Compared to before the election" describes the chamber on the eve of the vote, and the Duma's own count is the only primary figure for it. But the most-read results summaries are built the other way. The English Wikipedia summary of 2021 recorded United Russia's seat change as minus 19, counted from its 2016 result of 343, not from the seats it held on election eve (2021 Russian legislative election). If election-night tables count from 324 this time, that is the consensus of credible reporting the rule defers to first.
The gap matters far more for United Russia than for anyone else. New People's two baselines are 15 and 13, and the LDPR's are 22 and 21. United Russia's differ by fourteen.
Polymarket has used this sentence before, and settled it as "won"
This is template language, and the template has history. In November 2025 Polymarket ran "Which pact will gain the most seats in the Chile Senate election?", with the identical clause that resolution would rest "solely on the number of seats gained by the named pact." It settled Yes on Unidad por Chile, the pact that won 11 of the 23 seats up for election. By the English Wikipedia's account of that vote, Unidad por Chile unified the centre-left and left "without altering their combined seat total", while the right-wing Republican Party was the force that expanded (2025 Chilean general election). "Gained" was read as "won".
The July 2025 Japan precedent points the other way. Polymarket's "Which party gains most seats in Japan Councillors Election?" carried a title about gains but rules that said "wins the greatest number of the seats that are contested". It settled on the LDP. The Sanseitō leg, the one that captured the gain story, had traded $1,034,994 by the close, more than any other leg. The rules beat the title.
Put the two together and the Duma contract sits in an awkward place. Its rules, not just its title, say "gain", and they add "compared to before the election", which the Chile text lacked. That makes a pure "won the most seats" reading less likely here than it was in Santiago. It does not make it zero. We carry three readings:
- Counted from the outgoing chamber (United Russia 310): 55%
- Counted from the 2021 result (United Russia 324): 30%
- Read as "won the most seats", the Chile outcome: 15%
We made the same kind of argument about settlement text in our Venezuela leader piece, where the source the rules name mattered more than the headline, and in the Sweden prime minister call, where the date on the ticker was not the date that settles the contract.
Two state pollsters, two different challengers
Both of Russia's large state-aligned pollsters published election forecasts on 10 September. They agree on United Russia winning comfortably. They disagree on who comes behind it, and the gain market is mostly a bet on exactly that.
VTsIOM's forecast puts United Russia at 51–53%, the KPRF at 13–15%, and New People and the LDPR level at 9–11% each, with turnout of 51–53%. It describes A Just Russia's position as "unstable" at 4–6%. FOM's forecast, from fieldwork on 4 to 6 September, has United Russia lower at 47–49%, the KPRF at 14–17%, the LDPR clearly ahead of New People at 10–12% against 8–9%, and A Just Russia safely over the line at 6–7%. VTsIOM's weekly tracker for 31 August to 6 September had New People on 10.4% of all respondents against 9.9% for the LDPR (VTsIOM, 11 September 2026).
The track record is the reason not to take any of these ranges at face value. On 9 September 2021, VTsIOM forecast United Russia at 42%, within a range of 41–44%. The party took 49.82%. The same forecast had the LDPR at 11% and it finished on 7.55%. New People, forecast at 4–6%, landed at 5.32%.
The LDPR has made its target public. At its October 2025 congress Leonid Slutsky set the party the task of at least doubling its Duma faction from 22, Kommersant reported. Dmitry Elovsky, a political consultant, told the paper that would take 14–15% on the lists plus five to eight district wins, and that the LDPR "will be eating into everything held by the opposition parties, because United Russia will give up neither its ratings nor its single-mandate deputies" (Kommersant, 2 October 2025, translated from the Russian).
That sentence is the structure of the whole contract. The challengers' gains come out of the KPRF and A Just Russia. They do not come out of United Russia, and if A Just Russia drops under 5%, its list votes are discarded and every surviving party's share of the 225 list seats rises, United Russia's most of all.
There is also a subtle mismatch between Polymarket's own books. The third-place market prices the LDPR at 56% and New People at 35%, so traders expect the LDPR to finish ahead. Yet the gain market has New People at 17.85% and the LDPR at 3.05%. Both can be right, because the LDPR starts seven seats higher and has to finish more than seven seats ahead to out-gain New People. A 3.05% price says that almost never happens. FOM's forecast says it is a live outcome.
The seat market, the chart and the table
To turn this into a number, we simulated list shares around the two forecasts, allocated the 225 list seats by largest remainder with the 5% threshold, added a district block centred on about 201 United Russia wins, and then reweighted the runs so that United Russia's seat distribution matches Polymarket's own United Russia seat-count brackets. We are not trying to out-forecast that book on United Russia's total. We are asking what it implies once the rule is read correctly.
One check on the method: the reweighted model puts the LDPR third in seats 61.5% of the time and New People 34.9%. Polymarket's third-place book says 56% and 35%.
| Reading of "gain" | United Russia baseline | Our weight | United Russia | New People | LDPR |
|---|---|---|---|---|---|
| Change from the outgoing chamber | 310 | 55% | 76.0% | 17.0% | 6.8% |
| Change from the 2021 result | 324 | 30% | 42.1% | 44.1% | 13.8% |
| Most seats won (Chile precedent) | n/a | 15% | 99.15% | 0.4% | 0.15% |
| Weighted fair value | 100% | 69.3% | 22.6% | 7.9% | |
| Polymarket, 07:10 UTC | 78.0% | 17.85% | 3.05% |
Look at the first row. Even on the reading most favourable to United Russia, the model lands at 76%, below the market. The reason is that New People's gain is not fixed at ten. It adds fifteen seats or more in about one run in five, typically where A Just Russia misses the threshold and New People polls like VTsIOM's tracker, and United Russia finishing on 325 does not beat that.
Where United Russia's extra seats would come from
The party's route to a large gain runs through the districts. For the first time since the mixed system returned in 2014, United Russia nominated candidates in all 225 single-member districts, and it put up new faces in roughly 110 of the 198 it won in 2021 (Vedomosti, 1 July 2026).
"All 225" overstates it. The same Vedomosti count shows the party again fielding what the paper calls unelectable candidates against strong opposition deputies, including the KPRF's Sergey Kazankov, Oleg Smolin and Leonid Kalashnikov and A Just Russia's Anatoly Aksakov and Valery Gartung, and leaving two St Petersburg districts to agreed allies. Konstantin Kostin, head of the Civil Society Development Foundation, told Vedomosti that primaries decide candidates but "their results depend to a considerable extent on the intra-elite configuration in the regions and on the position and support of the main regional players" (translated from the Russian).
Redistricting adds a tailwind that the 2021 map did not have: seven new districts in the Russian-occupied regions of Ukraine, three in Donetsk, two in Luhansk and one each in Kherson and Zaporizhzhia, per Vedomosti. Electronic voting, which critics link to inflated results, covers 33 regions and about 48 million voters, according to the Moscow Times. On 10 August the Supreme Court removed Yabloko, the only party on the ballot calling for a swift end to the war, from the race (Meduza, 10 August 2026).
RelatedUS House Control 2026: Why Polymarket's 86.6% Isn't Settled
The price has chased all this. The United Russia leg opened in January, touched 91.5% on 9 January, fell to 53.5% on 6 June, sat near 68.5% on 8 September and has run to 78% since. New People peaked at 41.2% on 8 July.
Our call: 69%, and what moves it
Our fair value for United Russia gaining the most seats is 69%, against a market price of 78%. The market trades above our fair value on the favourite and below it on both challengers: New People at 17.85% against our 22.5%, the LDPR at 3.05% against our 8%. The KPRF, forecast by both pollsters below its 2021 share of 18.93%, is close to zero on our numbers.
Three seat outcomes cover the ground, using the market's own brackets. United Russia on 340 or more, which the seat book prices at 33.5%, settles this for United Russia under any reading. United Russia between 321 and 339, about 44%, is where the baseline decides everything: a win counted from 310, usually a loss counted from 324. United Russia on 320 or fewer, about 21%, most likely hands the New People leg or the LDPR the title whichever baseline is used.
What would change our mind? A Polymarket clarification naming the outgoing chamber as the baseline takes the Chile reading off the table and moves our fair value to about 76%; one naming the 2021 result drops it to about 42%. On the night, a CEC preliminary count with United Russia above 55% on the lists pushes it past 337 seats in most paths and makes the baseline argument moot. A Just Russia clearing 5% narrows the pool the challengers feed on.
Resolution should come quickly. Voting closes on 20 September, and in 2021 the CEC announced the final mandate distribution five days after polls closed. The legs carry an end date of 30 September 2026. Our US House control piece made the broader point: a race that looks settled and a contract that is settled are different things.
FAQ
Does United Russia need to win the election for this market?
No. Winning the most seats is a separate Polymarket contract, where United Russia trades at 99.15%. This one pays on the change in seats. A party can win a constitutional majority and still lose this market if another party's seat count rises further than its own does, measured against the chamber before the vote.
Which seat count is United Russia starting from?
The rules say "compared to before the election" but do not name a figure. The Duma's website shows 310 United Russia deputies on 11 September 2026. The party won 324 in 2021, and the Moscow Times cited 321 in July. We weight 310 at 55% and 324 at 30%, and keep 15% on the contract being read as "won the most seats".
Why is New People priced so far above the LDPR?
New People starts lower, at 15 seats against the LDPR's 22, so the same finishing position produces a bigger gain. VTsIOM's tracker also has New People slightly ahead. FOM disagrees, forecasting the LDPR at 10–12% against 8–9%. If FOM is right, the LDPR out-gains New People more often than a 3.05% price allows.
When will the market settle?
Voting runs from 18 to 20 September 2026. In 2021 the CEC announced the final mandate distribution on 24 September, five days after polls closed, and a similar timetable would let the market settle well before the legs' 30 September end date. The rules pay "Other" if results are not definitively known by 30 September 2027.
What happens to A Just Russia's seats if it misses 5%?
Its list votes are excluded and the 225 list seats are shared among the parties that cleared the threshold, in proportion to their votes. United Russia, as the largest party, takes the biggest share of that windfall. VTsIOM puts A Just Russia at 4–6% and calls its position unstable; FOM has it at 6–7%.
Disclaimer
This article is analysis and information, not investment advice or a recommendation to take any position. Prediction market contracts carry the risk of total loss of capital, and the fair values above are our own modelled estimates rather than statements of fact. Odds, poll figures and liquidity were accurate at the time of retrieval on 11 September 2026 and change continuously. Do your own research and never commit capital you cannot afford to lose.