2026 South Dakota Senate Race odds
Polymarket traders make Mike Rounds (R) the favorite for “South Dakota Senate Election Winner” at 94% (+0.4 pts in the last 24 hours), ahead of Brian Bengs (I) at 6%.
Prices refresh every few minutes. Probabilities are not predictions or advice, and you can lose what you trade.
Probability over the last 30 days
The top 3 outcomes right now.
All 3 outcomes and their odds
Probability is the share price. Decimal odds show what $1 returns if that outcome wins, before fees. American odds show the same price as a moneyline: +150 pays $150 on a $100 stake, −200 needs $200 to win $100.
Odds as of
- 94%
Mike Rounds (R)94%24h +0.4 ptsOdds 1.06US −1702Trade on Polymarket (affiliate link) - 6%
Brian Bengs (I)6%24h +0.1 ptsOdds 17.70US +1670Trade on Polymarket (affiliate link) - 0.1%
Democrat0.1%24h 0.0 ptsOdds 1000.00US +99900Trade on Polymarket (affiliate link)
Where this market stands
“South Dakota Senate Election Winner” is a Polymarket event with 3 open outcomes. Mike Rounds (R) leads at 94%, ahead of Brian Bengs (I) at 6%. Mike Rounds (R) is up 0.4 points over the last 24 hours and down 0.7 points over the past week. Traders have put $123K through the event so far, including $3,649 in the last 24 hours, and it is scheduled to end on November 4, 2026.
Whale trades in this market
The latest trades of $1,000 or more on this event, newest first.
Cb94C437EA5e6f088c6c0C143c592ab8EFBed bought No at 94%
Will Brian Bengs win the South Dakota Senate race in 2026?
kaxel78 bought No at 94%
Will Brian Bengs win the South Dakota Senate race in 2026?
PantheraUncia bought Yes at 94%
Will the Republicans win the South Dakota Senate race in 2026?
klli27 bought No at 94%
Will Brian Bengs win the South Dakota Senate race in 2026?
Vilgefortz bought Yes at 94%
Will the Republicans win the South Dakota Senate race in 2026?
QMG-CORE sold Yes at 92%
Will the Republicans win the South Dakota Senate race in 2026?
trampec bought No at 93%
Will Brian Bengs win the South Dakota Senate race in 2026?
SitsToPee bought No at 96%
Will the Democrats win the South Dakota Senate race in 2026?
Woeful-Wrinkle-Approach bought Yes at 96%
Will the Republicans win the South Dakota Senate race in 2026?
How this market resolves
This market will resolve according to the winner of the 2026 midterm South Dakota 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.
Rules are written by Polymarket and shown as published. WhaleSays does not settle markets.
Common questions
New to this? Our guide covers how to make your first trade.
- Who is the favorite in South Dakota Senate Election Winner?
- Mike Rounds (R) is the favorite at 94%, followed by Brian Bengs (I) at 6% and Democrat at 0.1%. Prices are the market's implied probabilities and update as traders buy and sell.
- Will the Republicans win the South Dakota Senate race in 2026?
- Polymarket traders give Mike Rounds (R) a 94% chance, which is decimal odds of 1.06 (American −1702): $1 staked on Mike Rounds (R) returns about $1.06 if it resolves Yes, before fees. In the last 24 hours the price moved up 0.4 points.
