Incumbent Republican Sen. Markwayne Mullin's March 2026 confirmation as DHS Secretary under President Trump vacated his seat, prompting Gov. Kevin Stitt to appoint energy executive Alan Armstrong, who plans to retire rather than seek the full term. This open race in deeply Republican Oklahoma—where no Democrat has won a Senate seat since 1990—drives trader consensus to 93% for a GOP victory, reflecting the state's consistent 30+ point Republican presidential margins, weak Democratic turnout, and historical base rates for red-state open seats exceeding 90% hold rates. Candidate filing closed April 3 with no high-profile Democrats emerging, focusing attention on the June 16 Republican primary. Upsets would require a GOP nominee scandal, national anti-Republican wave, or unprecedented Democratic funding surge ahead of the November 3 general election.
Experimental AI-generated summary referencing Polymarket data · Updated$11,552 Vol.
$11,552 Vol.

Republican
93%

Democrat
5%
$11,552 Vol.
$11,552 Vol.

Republican
93%

Democrat
5%
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 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.
Market Opened: Oct 13, 2025, 4:48 PM ET
Resolver
0x2F5e3684c...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 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.
Resolver
0x2F5e3684c...Incumbent Republican Sen. Markwayne Mullin's March 2026 confirmation as DHS Secretary under President Trump vacated his seat, prompting Gov. Kevin Stitt to appoint energy executive Alan Armstrong, who plans to retire rather than seek the full term. This open race in deeply Republican Oklahoma—where no Democrat has won a Senate seat since 1990—drives trader consensus to 93% for a GOP victory, reflecting the state's consistent 30+ point Republican presidential margins, weak Democratic turnout, and historical base rates for red-state open seats exceeding 90% hold rates. Candidate filing closed April 3 with no high-profile Democrats emerging, focusing attention on the June 16 Republican primary. Upsets would require a GOP nominee scandal, national anti-Republican wave, or unprecedented Democratic funding surge ahead of the November 3 general election.
Experimental AI-generated summary referencing Polymarket data · Updated



Beware of external links.
Beware of external links.
Frequently Asked Questions