TOTAL VOLUME:
$41.6b
24H VOL:
$113,284,831
24H TRANSACTIONS:
2,858,735,640
OPEN INTEREST:
$1,620,345,032
79,029
Markets across
1,359
events
MATCHED EVENTS:
138
PLATFORM COVERAGE:
4
Polymarket:
45%
VS.
Kalshi:
55%
Iowa
all
2 markets
Kalshi
Polymarket
consensus
News
Positive
Negative
Neutral
Hover marker for details
Vol.
·
Resolves Jan 3, 2027
Will Iowa have the smallest margin of victory in 2026 United States Senate elections?
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Description
This group forecasts which US Senate race in the 2026 election will have the smallest margin of victory. The margin of victory is calculated as the absolute difference in percentage points between the top two candidates' vote shares. Runoff and ranked-choice elections are resolved based on the final round.
PredictionHero - Resolution Divergence Alerts (RDA)
Divergence Detected
Issue: Polymarket considers all Senate races, while Kalshi focuses on a pre-defined list of states. Resolution sources also differ slightly.Hero tip: Focus on Polymarket markets as they consider all races, providing a more comprehensive view of the closest Senate contest.Critical divergence points:
- Polymarket: The market will resolve according to the US Senate race which has the smallest margin of victory, considering all regular and special Senate elections scheduled as of October 31, 2026. Margin of victory is the absolute difference between the percentages of valid votes received by the first- and second-place candidates. Resolution source is a compilation of state election authorities and credible reporting.
- Kalshi: The market resolves to 'Yes' if a specific listed state (Minnesota, New Hampshire, etc.) has the smallest margin of victory among *all* elections as of Jan 3, 2027. This implies a limited scope to the states explicitly listed.
Polymarket
The 2026 midterm elections are scheduled to be held on November 3, 2026. This market will resolve according to the US Senate race which has the smallest margin of victory. For the purpose of this market, the “margin of victory” is defined as the absolute difference between the percentages of valid votes received by the first- and second-place candidates. Percentages of the valid votes received by each candidate will be determined by dividing the total number of valid votes each of the top two candidates receives by the sum of all valid votes cast in the election. For elections that include runoffs, ranked-choice, or other multi-round elections, the relevant margin of victory will be that of the round in which the winner is determined. If two state margins of victory are identical, this market will resolve to the tied state whose name comes first alphabetically. This market will consider 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. The resolution source for this market will be a compilation of all of the relevant state election authorities responsible for certifying statewide elections, however, a consensus of credible reporting may also be used.
Kalshi
The market resolves based on which state's 2026 U.S. Senate race has the smallest margin of victory as of January 3, 2027. Margin of victory is defined as the absolute percentage point difference between the first and second-place finishers. For races with more than two candidates, only the gap between the top two candidates is considered. In races using ranked-choice or instant-runoff voting, the margin from the final round determines the outcome. If official results are unavailable by the deadline, preliminary results are used provided at least 95% of the expected vote has been counted. If multiple races have identical margins—tied to the hundredth of a percentage point—the payouts are split equally among the tied options. Any election postponed or lacking sufficient results by the deadline automatically resolves to 'No' for that market.