IL-09 House Election Margin of Victory
PM $11.9K
1
10
IL-09 House Election Margin of Victory
PM $11.9K
1
10
Current odds
Snapshot from
As of Oct 20, 2026, 6:00 PM UTC, the highest-priced outcome on Polymarket is Democrat 45-50% at 33.5%.
Polymarket
- Democrat 45-50%33.5%
- Democrat 40-45%24.3%
- Democrat 50-55%18.5%
- Democrat 55-60%17%
- Democrat 35-40%7.1%
Yes prices. They are not order quotes; check each platform's rules, fees and live prices before trading.
AI Analysis
Trader mode: Market mechanics, assumptions and risks
PM $11.9K
Reported volume · provider units
10
Saved contracts
0
Same-question pairs
Source snapshot: Oct 20, 2026, 6:00 PM UTC
About This Event
The 2026 IL-09 House election is currently expected to be held on November 3, 2026. This market will resolve according to the margin of victory between the top two candidates in the specified election. The "margin of victory" is defined as the absolute difference between the percentages of valid votes received by the first-place and second-place candidates. Percentages of the valid votes received by each candidate will be determined by dividing the total number of valid votes each of the top two candidates receives by the sum of all valid votes cast in the election. For purposes of this market, candidates nominated by the Democratic & Republican Parties will represent the options for "Democrat" and "Republican," respectively. Independent candidates will not represent options for either party. The candidates may be named in the contract for the convenience of traders. In the event that any named candidate is replaced as the nominee of their respective party prior to election day, the name in the contract will be updated and the market will resolve based on the replacement nominee of the party. If the reported value falls exactly between two brackets, then this market will resolve to the higher margin bracket. If two or more candidates tie for the most valid votes in this election, and the tie is between two candidates listed, this market will resolve to the lowest margin bracket for the candidate whose ballot-listed last name comes first in alphabetical order. If the tie is between a listed candidate and an unlisted candidate, this market will resolve to the lowest margin bracket for the listed candidate. If the tie is between two or more unlisted candidates, this market will resolve to "Other." If the listed candidate is represented in this market group as "Republican" or "Democrat" their ballot-listed last name will still be used for tiebreaking. This market will resolve based on the official vote count once the count has been made official. If the election results are not known definitively by June 30, 2027, 11:59 PM ET, this market will resolve to "Other". If a recount is initiated before the vote total has been made official, the market will remain open until the recount is completed and the vote is made official. The primary resolution source for this market will be the official results of the 2026 IL-09 House election as published by the state electoral authority responsible for certifying the results of the election; however, an overwhelming consensus of credible reporting may also be used.
This analysis is awaiting a background update, so its prices may be older than the odds above.
Snapshot observed 2026-10-15T21:00:05.939Z. This analysis describes that snapshot and is not a live news update.
What the contract measures
The Polymarket event sets brackets for the margin of victory in the 2026 IL-09 House election [1]. The margin is "the absolute difference between the percentages of valid votes received by the first-place and second-place candidates" [1]. Only Democratic and Republican Party nominees count as options, and independent candidates do not represent either party [1]. If a reported value falls exactly between two brackets, the market resolves to the higher bracket [1]. Ties and recounts follow separate rules, and if results are not known definitively by June 30, 2027, 11:59 PM ET, the market resolves to "Other" [1]. The source describes the election as "currently expected to be held on November 3, 2026," and the provider lists an end time of 2026-11-04T04:59:00.000Z [1]. That listed time is a provider field, not a confirmed closing event. Resolution depends on the official count as certified by the state electoral authority [1].
Reading the snapshot
The provider observed these prices at 21:00 UTC on October 15, 2026, and the source was retrieved at 23:42 UTC that day [1]. These figures describe that earlier moment only. They are not executable quotes or verified probabilities. The nine margin brackets show Yes prices from 0.049 for the 0%-20% bracket to 0.2825 for the 45%-50% bracket, with 0.247 for 40%-45% and 0.175 for 50%-55% [1]. The "60% or more" bracket shows 0.051 [1]. A separate contract asking whether the Republican Party candidate will win shows Yes at 0.02 [1]. Because it is a different contract and not a margin bracket, it should not be read as part of the margin distribution.
The nine margin Yes prices sum to about 1.17, so in this snapshot they do not form a normalized distribution. Price differences between contracts do not by themselves indicate an opportunity, since the evidence does not include fees, liquidity, or execution conditions.
What remains uncertain
The sample includes 10 of 10 saved markets for this event, and the provider reports no partial sample [1]. The source also states that the sample warning "does not establish that the providers list every possible real-world outcome" [1]. No other platform is included, so this analysis makes no cross-platform comparison. The excerpt contains no trading volume or trader count, and it gives no explanation for the price levels. The election date is described only as expected. A recount, a replacement nominee, or the certified result could affect how the contract resolves [1].
References
- Polymarket: IL-09 House Election Margin of Victory. Provider data observed 2026-10-15T21:00:05.939Z.
AI-generated analysis based on market data. Not financial advice.
Saved Oct 15, 2026 UTCThis saved content is awaiting a background update. It may contain outdated claims; use the dated market data and provider rules for the latest available information.
Overview
The IL-09 House Election Margin of Victory contract is a Polymarket event about the 2026 U.S. House election in Illinois's 9th congressional district. According to the provider's rules, the 2026 IL-09 House election is currently expected to be held on November 3, 2026 [1]. The Wikipedia article on 2026 House elections in Illinois says the state will elect 17 representatives, one from each congressional district, on the same date, and that primary elections were held on March 17, 2026 [2]. The election has not yet taken place, so the contract concerns a future result. The contract does not ask which party wins. It asks how large the winning margin will be. The provider defines the "margin of victory" as "the absolute difference between the percentages of valid votes received by the first-place and second-place candidates" [1]. Each percentage is the candidate's valid votes divided by the total valid votes cast in the election [1]. Candidates nominated by the Democratic and Republican Parties represent the "Democrat" and "Republican" options, and independent candidates do not represent either party [1]. The event is organized into margin brackets, such as 0% to 20%, 20% to 30%, and 60% or more, along with a separate contract asking whether the Republican Party candidate will win [1]. Under the provider's rules, if a reported value falls exactly between two brackets, the market resolves to the higher margin bracket [1].
Historical Context
The supplied background on earlier House elections covers a different contest. The 2018 United States House of Representatives elections were held on November 6, 2018, were midterm elections during President Donald Trump's first term, and chose representatives from all 435 congressional districts [3]. This is general background on the federal House election cycle and does not describe the IL-09 race or its history.
Why It Matters
The contract measures the size of the victory margin in one House race rather than the overall winner. Because the margin is the gap between the top two candidates' shares of valid votes, it depends on the vote shares of both leading candidates, not only on who finishes first [1]. The brackets split possible outcomes into ranges, so each contract covers a specific range of margins. The rules also set how the result will be determined. The primary resolution source is the official results of the 2026 IL-09 House election as published by the state electoral authority responsible for certifying results, though an overwhelming consensus of credible reporting may also be used [1]. The market resolves on the official vote count once it has been made official [1]. If a recount starts before the total is official, the market stays open until the recount is completed and the vote is made official [1].
Snapshot context
The latest published provider snapshot for this topic was observed on 2026-10-15 at 21:00 UTC. It contains listings from Polymarket. Market descriptions and listed closing times define the contracts; they do not establish that the real-world outcome has occurred. This article does not include a separately verified news update. [1]
Frequently Asked Questions
How is the margin of victory calculated?
The margin is the absolute difference between the percentages of valid votes received by the first-place and second-place candidates. Each percentage is found by dividing a candidate's valid votes by the total valid votes cast in the election [1].
What happens if a named candidate is replaced before election day?
If a named candidate is replaced as their party's nominee before election day, the name in the contract will be updated and the market will resolve based on the replacement nominee [1].
How are ties handled?
If two listed candidates tie for the most valid votes, the market resolves to the lowest margin bracket for the candidate whose ballot-listed last name comes first alphabetically. If the tie is between a listed candidate and an unlisted candidate, it resolves to the lowest margin bracket for the listed candidate. If the tie is between two or more unlisted candidates, it resolves to "Other" [1].
What happens if the results are not known by the deadline?
If the election results are not known definitively by June 30, 2027, 11:59 PM ET, the market resolves to "Other" [1]. This is a resolution rule and does not describe an expected event date.
Does the Republican winner contract use the same margin brackets?
No. The Republican contract asks whether the Republican Party candidate will win the 2026 IL-09 House election, while the other contracts in the event are margin brackets for the Democratic Party candidate [1].
AI-written background. References identify the evidence used; Wikipedia links under Learn More are additional reading. Prices and provider rules are dated snapshots. This is not financial advice.
Related prediction markets
Prices are catalog snapshots and may have changed. Check each market's rules and observation time.
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