PolymarketPoliticsDevelopingUpdated 8m ago

Will the Democrats win the Illinois Senate race in 2026?

As of Oct 12, 2026, 7:02 PM ET, Polymarket priced this market at 98.2% (little changed over 24 hours). It had $1.6K traded in the past 24 hours, $31K of order-book liquidity and a bid-ask spread of 1.6 pts. probcast.co rates the support behind this price as moderate.

Market probability
98.2%
Little changed over 24 hours

Thin market where small orders can move the price, with broad trading across many accounts.

Price historyPolymarket

Source: Polymarket price history

How credible was the move?

Methodology →

Move validity

Moderate

Consensus stability

Stable

Contract clarity

High

Can you trust this price?

Two different questions: how hard the price is to move, and whose trading set it.

Market capacity

How hard is it to move this price?

ThinTight spread

Order-book liquidity

$31K

Bid-ask spread

1.6 pts

24h volume

$1.6K

Total volume

$18.8K

The visible order book runs out before the price would rise 5 pts — little resting money above the current price.

Little money on the book — a modest order can move this price, so treat swings with care.

Who's trading

Whose opinion is this price?

Broad participation
16%of the traded money came from the single largest account

Accounts

79

Trades

200

over 192 days

Largest order

$1.6K

$9.5K traded across these 200 trades (last 192 days).

Many independent accounts traded — the price reflects a crowd, not one trader.

Recent trade activity$9.5K traded

From the latest trade tape (most recent 200 prints) — a live activity sample, not a lifetime total.

What this market actually measures

This market will resolve according to the winner of the 2026 midterm Illinois U.S. Senate election, inclusive of any run-offs.

This summary shows the opening of the venue's official rules. ProbCast has not yet generated an independent plain-English interpretation for this contract — review the full rules before relying on it.

View full official resolution rules

This market will resolve according to the winner of the 2026 midterm Illinois U.S. Senate election, inclusive of any run-offs. A candidate shall be considered to represent a party in the event that he or she is the nominee of the party in question. Candidates other than the Democratic or Republican nominee (e.g., Greens, Libertarian, independent) may be added at a later date. Candidates who run as independents will not be encompassed by the “Democrat” or “Republican” options regardless of any affiliation they may have with the 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. The resolution source for this market is the Associated Press, Fox News, and NBC. This market will resolve once all three sources call the race for the same candidate. If all three sources haven’t called the race in this state for the same candidate, this market will resolve based on the official certification.

What could move this market next?

  • The market's deadline arrivesNovember 3, 2026 at 11:59 PM ET

    The contract must resolve based on what has happened by this date.

Derived from the contract's own mechanics as of Oct 12, 7:10 PM ET. ProbCast does not list scheduled meetings, announcements, or data releases it cannot verify.

Advanced analysis (experimental)

Research signals — these models are still accumulating the history needed for full validation, and they can disagree with the headline read. Model confidence: low · expected error ±15 pts.

Thin marketLegacy movement classifier: watch

What's happening

medium classifier confidence
Thin market

Thin book and/or wide spread. Small orders can move this price disproportionately, so any single print is noisy and easily overread.

  • Book runs out before absorbing a 5-pt move (fragile depth)

Read with caution —Read the latest price with caution; conditions make it an unreliable summary right now.

More details — reliability score, dynamics, durability
Reliability score
24Low
Where the price path tends to go next1017 observed
  • Choppy / mean-reverting96%
  • Stable consensus2%
  • Illiquid / quiet1%

Short-term motion of the price line (~1h), distinct from the environment above — not a prediction of the final outcome.

DurabilityHigh· half-life ~4w
PredictabilityStable

Secondary read: leaning toward Stale price.

A read-only classification of the market environment — how much weight the current price deserves as a read of consensus. It describes conditions, never a trade.

Change (pts)1H0.06H0.024H0.07D0.0

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