53

Decided by

The Republican Party's seat count in the U.S. Senate resulting from the 2026 midterm election scheduled for November 3, 2026.§1

Runoffs

Runoffs for qualifying elections determine attribution of the relevant seat, even if held after November 2026.§3

Vacant seats

Vacant seats with no November 2026 election scheduled as of October 31, 2026 go to the party of the most recent member to hold the seat.§4

Party switch

If a member-elect changes party or vacates their seat before Congress organizes, the seat goes to the party under which they were elected.§6

Independent caucuses

Independents who caucus with, or announce intent to caucus with, the Republican party are included in the count.§9

Counted

All regular and special Senate elections determining representation in the 120th Congress, scheduled for November 2026 as of October 31, 2026.§2

Source

Official information from relevant state electoral authorities, the U.S. Congress, and a consensus of credible reporting.§12

Restated in plain words from the rules text. Each § opens the sentence it comes from; the rules text governs.

Shares = Yes minus No for each trader. Record counts every settled bet, including losses never cashed in. Polymarket's own contracts are left out.

How these markets fit together

Exactly one of this event's 11 outcomes pays $1. Their prices add up to 105.2¢ right now.

• ≤47 38.5¢
• 48 16.5¢
• 49 12.5¢
• 50 12.5¢
• 51 9.0¢
• 52 6.3¢
• 53 5.1¢
• 54 2.0¢
• 55 1.4¢
• 57+ 0.8¢
• 56 0.7¢

These 11 outcomes add up to 105.2¢. Only one can win, so a fair set adds up to about 100¢.