PolymarketPoliticsDevelopingUpdated 10m ago

Will the Republican Party hold exactly 53 Senate seats after the 2026 midterm elections?

As of Oct 11, 2026, 4:24 PM ET, Polymarket priced this market at 5.1% (little changed over 24 hours). It had $51.6K traded in the past 24 hours, $131.9K of order-book liquidity and a bid-ask spread of 0.2 pts. probcast.co rates the support behind this price as strong.

Market probability
5.1%
Little changed over 24 hours

Deep, easy-to-trade market, traded by a small group of accounts.

Price historyPolymarket

Source: Polymarket price history

How credible was the move?

Methodology →

Move validity

Strong

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?

DeepTight spread

Order-book liquidity

$131.9K

Bid-ask spread

0.2 pts

24h volume

$51.6K

Total volume

$143.9K

It would take roughly $3.7K of buying to move the price up by ~5 pts.

Lots of money on the book and a tight spread — a single ordinary order can't move this price much.

Who's trading

Whose opinion is this price?

A few accounts
60%of the traded money came from the single largest account

Accounts

82

Trades

200

over 141 days

Largest order

$2.6K

$4.4K traded across these 200 trades (last 141 days).

A small group of accounts did most of the trading — neither one whale nor a broad crowd.

Recent trade activity$4.4K 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 Republican Party’s seat count in the United States Senate as a result of the 2026 United States midterm election scheduled for November 3, 2026. The seat count includes all regular and special Senate elections that determine representation in the upcoming 120th Congress and are scheduled to take place in November 2026 as of October 31, 2026.

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 Republican Party’s seat count in the United States Senate as a result of the 2026 United States midterm election scheduled for November 3, 2026. The seat count includes all regular and special Senate elections that determine representation in the upcoming 120th Congress and are scheduled to take place in November 2026 as of October 31, 2026. Runoffs for qualifying elections will determine attribution of the relevant seat, even if they take place after November 2026. Vacant seats for which no election or special election to fill the seat is scheduled to take place in November 2026 as of October 31, 2026 will be treated as held by the party affiliation of the most recent member to hold that seat. For seats contested in the specified election, seats are attributed to the party under which the member was elected. If a member-elect changes party affiliation, or vacates their seat, between election day and the formal organization of Congress, the seat is attributed to the party under which the member was elected. For seats not contested in the specified election, seats are attributed to the party that holds the seat as of the date of the election. If a current sitting member of the U.S. Senate who is not up for election changes party affiliation or vacates their seat after the date of the election, the seat is attributed to the party under which the member was affiliated at the time of the election. Senate members elected as independents who formally caucus with, or, for newly elected members, who announce their intent to caucus with, the Republican party are included in the count. If the caucus decisions of members of the Senate elected as independents cannot be determined on the date of the election, this market may remain open until the earlier of (i) an announcement from the relevant members of their intents to caucus, or (ii) January 4th, 11:59 PM ET of the following calendar year. If no such announcement is made by January 4th, 11:59 PM ET of the following calendar year, the member will not count towards the seat count of any party. The resolution sources for this market will be official information from relevant state electoral authorities, the United States Congress, and a consensus of credible reporting.

What could move this market next?

  • The scheduled event takes placeNovember 10, 2026 at 3:28 PM ET

    The contract resolves on the event's outcome.

Derived from the contract's own mechanics as of Oct 11, 4:34 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: high · expected error ±9 pts.

Trading normallyLegacy movement classifier: watch

What's happening

medium classifier confidence
Trading normally

Liquid, two-sided, and calm. The current price reads as settled consensus — the latest print is a reasonable summary of what the market believes.

  • Liquid, two-sided, and calm — price behaving as settled consensus

The latest price is a usable but caveated read — weigh it with the market state.

More details — reliability score, dynamics, durability
Reliability score
55Medium
Where the price path tends to go next255 observed
  • Stable consensus94%
  • Trend continuation3%
  • Choppy / mean-reverting3%

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 Quote-driven.

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.

Market data

24h volume

$51.6K

Liquidity

$131.9K

Total volume

$143.9K

Category
Politics
Venue
Polymarket
Open interest
—
Spread
0.2 pts
Best bid
5.0%
Best ask
5.2%
7-day range
5.1% – 5.1%
Resolves
Nov 10, 2026
Change (pts)1H0.06H0.024H0.07D0.0

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