Short Answer

Both the model and the market overwhelmingly agree that turnout Above 200k is most likely for the 2026 South Carolina Republican Senate special primary runoff, with only minor residual uncertainty. Reported voter turnout of 368,723 provides strong evidence for this outcome.

1. Market Behavior & Drivers

This market opened with a high probability of YES at 70.0% before experiencing extreme volatility in the week preceding the August 25, 2026, runoff. The price collapsed by 53.0 percentage points on August 20, followed by a partial recovery and a subsequent 13.0 point drop on August 22. This latter decline was driven by reports of local election officials citing voter fatigue from a compressed election schedule. The market traded in a wide range from a low of 12.0% to a high of 99.0%, demonstrating significant uncertainty among participants regarding final voter turnout.
The definitive market move was a 61.0 percentage point spike on August 25, from 37.0% to 98.0%. This price action was a direct response to the official reporting of final voter turnout figures following the special primary runoff, in which Darline Graham won the Republican nomination. Total volume of 135,281 contracts suggests active participation, with trading patterns reflecting sharp reactions to new information rather than a gradual trend. The market established an early high at 70.0% and a clear floor in the 12.0-17.0% range during peak uncertainty.
Market sentiment was initially confident but became highly reactive and bearish as the election approached. The sharp repricing based on official concerns about voter fatigue suggests traders placed significant weight on that narrative. The final, decisive spike to near-certainty upon the release of official data indicates the market efficiently processed the definitive results, resolving the prior uncertainty and confirming the YES outcome.
  • The reported 368,723 votes secures a "Yes" outcome for turnout thresholds below 375,000.
  • Reported turnout of 368,723 votes indicates a "No" outcome for thresholds at or above 375,000.
  • Donald Trump's late endorsement likely mobilized significant voter turnout for Darline Graham.

Who Wins and Why

Outcome Market Model Why
Above 325k 99.0% 100.0% The reported turnout of 368,723 votes is above the 325,000 threshold.
Above 300k 99.0% 100.0% The reported turnout of 368,723 votes is above the 300,000 threshold.
Above 350k 99.0% 100.0% The reported turnout of 368,723 votes is above the 350,000 threshold.
Above 375k 2.0% 0.0% The reported turnout of 368,723 votes is below the 375,000 threshold.
Above 275k 99.0% 100.0% The reported turnout of 368,723 votes is above the 275,000 threshold.

Current Context

Darline Graham won the South Carolina Republican Senate runoff. She defeated U.S. Representative Ralph Norman in the August 25, 2026, special primary runoff, securing 52.45% of the vote compared to Norman's 47.55% [1]. This special election was necessitated by the July 11, 2026, death of Senator Lindsey Graham. His sister, Darline Graham, was temporarily appointed to the seat by Governor Henry McMaster before campaigning for the full-term nomination [2][3][4][5][6][7]. Graham will advance to face Democratic nominee Dr. Annie Andrews in the November 3, 2026, general election [2][3][5].
Runoff voter turnout exceeded participation in the initial primary election. Total voter turnout for the August 25, 2026, runoff was 368,723 votes, including at least 63,712 early ballots cast [8][9][1]. This level of engagement was higher than the initial special primary held on August 11, 2026 [9]. President Donald Trump significantly influenced the outcome through his active endorsement and campaigning for Darline Graham, which included a rally in Myrtle Beach and a tele-rally, framed as a referendum on his political influence [2][10][11].
Sources (11)
  1. 12026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  2. 2Sen. Darline Graham projected to win runoff in South Carolina GOP Senate primary, defeating Rep. Ralph Norman - CBS Newscbsnews.com
  3. 3Darline Graham Nordone Wins Runoff in South Carolina’s Special GOP Senate Primarytime.com
  4. 4Sen. Darline Graham wins GOP primary runoff to replace her late brother in US Senate - ABC Columbiaabccolumbia.com
  5. 5Primary runoff will determine Lindsey Graham's (R) replacement on August 25 - Ballotpedia Newsnews.ballotpedia.org
  6. 6Primary election report notice - South Carolina Republican...fec.gov
  7. 7Lindsey Graham's death will set off a special primary election for a Senate seat that's open for the second time since 1956 - Ballotpedia Newsnews.ballotpedia.org
  8. 8Early voting wraps up in South Carolina’s Republican U.S. Senate runofflive5news.com
  9. 9High Early Turnout Raises Stakes in Tight South Carolina Senate Runoff - CRBC Newscrbcnews.com
  10. 10Sen. Darline Graham wins South Carolina GOP Senate race, defeating Rep. Ralph Normannbcnews.com
  11. 11Darline Graham projected winner for US Senate GOP nominationpostandcourier.com

2. Price Chart

Historical Price (Probability)

Outcome probability
Date

3. Significant Price Movements

Notable price changes detected in the chart, along with research into what caused each movement.

Outcome: Above 375k

📉 August 26, 2026: 18.0pp drop

Price decreased from 20.0% to 2.0%

What happened: The 18.0 percentage point drop referenced in the query appears to correspond to an unrelated primary runoff in South Carolina's 1st Congressional District in June 2026, not the August 2026 Senate special primary runoff market [1]. For the South Carolina Republican Senate special primary runoff on August 25, 2026, the primary driver for a price drop in an "Above 375k" turnout contract was the official tabulation of votes [2]. Total turnout reached 368,723 votes, falling below the 375,000 threshold, which led prediction markets to adjust as election returns arrived [2][3][4]. Social media was not a primary driver, as the market movement was directly linked to factual election outcomes.

Outcome: Above 350k

📈 August 25, 2026: 85.0pp spike

Price increased from 9.0% to 94.0%

What happened: No social media activity was identified as driving the 85.0 percentage point market price spike, as no relevant posts or narratives were found in the provided research. The primary driver was the official reporting of the final voter turnout for the South Carolina Republican Senate special primary runoff, coinciding with the market date of August 25, 2026, and continuing into August 26 [5][6][2]. The confirmed turnout of 368,723 votes definitively exceeded the 350,000 threshold [6][2], causing the market predicting "Above 350k" to surge as the outcome was realized. Therefore, social media was irrelevant, as no related activity was found in the provided research.

📉 August 24, 2026: 26.0pp drop

Price decreased from 37.0% to 11.0%

What happened: The primary driver of the 26.0 percentage point price drop on August 24, 2026, for the "Above 350k" turnout outcome in the South Carolina Republican Senate special primary runoff was likely the traditional news reporting of early voting statistics. On August 24, news outlets announced that approximately 63,700 early ballots were cast [7]. This figure, while higher than initial primary early voting [7], may have been interpreted by market participants as insufficient to confidently project a total turnout above 350,000, especially given the previous primary's 335,910 votes [8]. This news appeared to coincide with the price move, causing a downward revision of expectations. Social media was irrelevant as a primary driver, as the only related post [9] appeared after election results were available.

📈 August 23, 2026: 22.0pp spike

Price increased from 15.0% to 37.0%

What happened: Reports emerging around August 23, 2026, indicating strong early voting for the South Carolina Republican Senate special primary runoff, likely caused the prediction market price spike. With over 60,000 ballots cast during the early voting period [10], this suggested increased voter engagement compared to the initial primary's approximately 336,000 total votes [11][8], making the "Above 350k" outcome for the August 25 runoff more probable. This traditional news appeared to LEAD the market move. Social media activity was not identified as a primary driver based on available information.

Outcome: Above 325k

📉 August 22, 2026: 13.0pp drop

Price decreased from 39.0% to 26.0%

What happened: The primary driver for the 13.0 percentage point price drop on August 22, 2026, was likely the growing concern among local election officials about voter fatigue [12]. Officials cited the compressed election calendar leading up to the August 25, 2026, runoff as a reason for expected lower participation, which would depress turnout expectations [12]. This traditional news narrative, suggesting reduced voter engagement, appears to have coincided with the market re-evaluation. Social media activity was not identified as a primary driver.
Sources (12)
  1. 1Jenny Honeycutt (R) defeated Mark Smith (R) in the Republican primary runoff for South Carolina's 1st Congressional District - Ballotpedia Newsnews.ballotpedia.org
  2. 22026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  3. 3South Carolina Republican Senate special primary runoffkalshi.com
  4. 4South Carolina Senate Runoff Turnout: Kalshi's 375K...oddsshopper.com
  5. 5Darline Graham wins special GOP primary runoff for US Senate in South Carolina, AP projectswbtv.com
  6. 6South Carolina U.S. Senate Special Runoff Election Resultsnytimes.com
  7. 7High Early Turnout Raises Stakes in Tight South Carolina Senate Runoff - CRBC Newscrbcnews.com
  8. 82026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  9. 9Get live 2026 South Carolina U.S. Senate Republican...facebook.com
  10. 10Early voting beats first primary turnout ahead of SC Senate runoff — see which county ledwistv.com
  11. 11What to expect in South Carolina’s special U.S. Senate primary runoff | AP Newsapnews.com
  12. 12Early voting ends in South Carolina GOP Senate runoff as officials cite voter fatigueabcnews4.com

4. Market Data

Contract Snapshot

This contract concerns the voter turnout in the South Carolina Republican Senate special primary runoff. It resolves to "Yes" if the final, officially certified voter turnout is above 300,000 votes, and "No" if it is 300,000 votes or less. Settlement occurs only after results are officially certified, with a maximum payout date listed as August 25, 2027.

Available Contracts

Market options and current pricing

Outcome bucket Yes (price) No (price) Last trade probability
Above 225k $1.00 $0.01 99%
Above 250k $1.00 $0.01 99%
Above 275k $1.00 $0.01 99%
Above 300k $1.00 $0.01 99%
Above 325k $1.00 $0.01 99%
Above 350k $1.00 $0.01 99%
Above 200k $1.00 $0.01 97%
Above 375k $0.02 $1.00 2%
Above 400k $0.01 $1.00 1%

Market Discussion

The South Carolina Republican Senate special primary runoff on August 25, 2026, saw approximately 368,723 votes cast [1]. Voter turnout showed significant early interest, with over 65,000 early or absentee ballots cast—approximately 3.5% higher than the turnout in the initial primary, particularly in areas such as Spartanburg and Greenville [2][3]. Pre-election commentary highlighted how high early turnout raised the stakes in the competitive runoff, with concerns that the contentious race could potentially fracture party unity [3].

Sources (3)
  1. 12026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  2. 2Early voting wraps up in South Carolina’s Republican U.S. Senate runofflive5news.com
  3. 3High Early Turnout Raises Stakes in Tight South Carolina Senate Runoff - CRBC Newscrbcnews.com

5. How did voter turnout in the August 2026 special runoff compare to previous South Carolina Republican primary runoffs?

Runoff Votes Cast368,723 votes (August 25, 2026) [1]
Initial Primary Participants336,000 participants (August 11, 2026) [2]
First SC Senate Runoff Since2004 [3]
South Carolina's 2026 special Senate runoff experienced unusually high voter turnout. The August 25, 2026 Republican Senate special primary runoff recorded 368,723 votes cast [1], representing a notable increase from the approximately 336,000 participants in the initial special Republican Senate primary on August 11, 2026 [2]. This rise in turnout for the runoff, which included a 3.5% higher early voting turnout compared to the primary, contrasts with typical historical trends in South Carolina where primary runoff elections usually experience a drop in participation [4].
This special primary runoff was a historically significant event for South Carolina. It marked the first U.S. Senate election runoff in the state since 2004 [3]. The necessity for this election arose following the death of incumbent Senator Lindsey Graham on July 11, 2026 [5].
Sources (5)
  1. 12026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  2. 2What to expect in South Carolina’s special U.S. Senate primary runoff | AP Newsapnews.com
  3. 3Primary runoff will determine Lindsey Graham's (R) replacement on August 25 - Ballotpedia Newsnews.ballotpedia.org
  4. 4South Carolina GOP Governor’s Race Heads to Runoff Tuesday – TV Delmarva Channel 33tvdelmarva.com
  5. 5Lindsey Graham's death will set off a special primary election for a Senate seat that's open for the second time since 1956 - Ballotpedia Newsnews.ballotpedia.org

6. What impact did Donald Trump's late-stage endorsement of Darline Graham have on voter mobilization for the 2026 runoff?

Darline Graham's Vote Share52.45% [1][2]
Total Voter Turnout368,723 votes [1]
Trump's PAC Advertising Push$830,000 [3][4][5]
Donald Trump's late-stage endorsement significantly mobilized voters for Darline Graham's 2026 primary victory. His active support was a critical factor in Darline Graham's success in the South Carolina Republican Senate special primary runoff, substantially contributing to her victory [3][4][5][6][7]. This support included an in-person campaign visit to Myrtle Beach on August 21, 2026, where he directly appealed to the "MAGA crowd," proving particularly effective in areas like Horry County where his rally was held [3][5][4]. Furthermore, Trump's allied super PAC, MAGA Inc., provided an $830,000 late advertising push, showcasing his deep intervention [3][4][5].
Graham secured victory in the runoff with Trump's acknowledged decisive support. Darline Graham ultimately won the runoff against Ralph Norman on August 25, 2026, by securing 52.45% of the vote [1][2]. The election saw a total voter turnout of 368,723 votes [6][7][1]. Both the candidates involved and external observers recognized the former President's endorsement as a decisive element in the outcome of this special primary runoff [6][7].
Sources (7)
  1. 12026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  2. 2United States Senate election in South Carolina, 2026ballotpedia.org
  3. 3Trump's endorsement pivotal in Darline Graham's SC Senate primary winusatoday.com
  4. 4Sen. Darline Graham wins South Carolina GOP Senate...nbcnews.com
  5. 5Darline Graham wins SC Senate runoff backed by Trump and MAGA Inc | Fox Newsfoxnews.com
  6. 6AP Interview: Ralph Norman questions Trump's endorsement...ap.org
  7. 7Primary runoff will determine Lindsey Graham's (R) replacement on August 25 - Ballotpedia Newsnews.ballotpedia.org

7. Which official sources published the final certified vote counts for the 2026 South Carolina Republican Senate special primary runoff?

Election DateAugust 25, 2026 [1][2][3]
Certified Results StatusNot yet published as of August 26, 2026 [4][5][1][2][6]
Projected WinnerDarline Graham (by media outlets) [7][8][9][10]
Official certified results for the runoff are not yet available. The South Carolina State Election Commission (SEC), through its website scvotes.gov, serves as the official source for certified election results in South Carolina [4]. However, as of August 26, 2026, the day following the August 25, 2026, South Carolina Republican Senate special primary runoff, the official certified final vote counts have not yet been published by the South Carolina State Election Commission or other state authorities [4][5][1][2][6].
Media outlets projected a winner based on unofficial tallies. The 2026 South Carolina Republican Senate special primary runoff took place on August 25, 2026 [1][2][3]. Based on unofficial vote tallies, several media organizations, including The Associated Press, NBC News, and CBS News, projected Darline Graham as the winner of the special primary runoff [7][8][9][10].
Sources (10)
  1. 1United States Senate election in South Carolina, 2026...ballotpedia.org
  2. 22026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  3. 3Primary runoff will determine Lindsey Graham's (R) replacement on August 25 - Ballotpedia Newsnews.ballotpedia.org
  4. 4Election Results - SC Votesscvotes.gov
  5. 5Prep for the 2026 Special Republican Primary Runoffscvotes.gov
  6. 6Darline Grahamballotpedia.org
  7. 7Sen. Darline Graham wins South Carolina GOP Senate race, defeating Rep. Ralph Normannbcnews.com
  8. 8Sen. Darline Graham projected to win runoff in South Carolina GOP Senate primary, defeating Rep. Ralph Norman - CBS Newscbsnews.com
  9. 9Darline Graham, Ralph Norman go head-to-head in South Carolina's GOP Senate runoff | AP Newsapnews.com
  10. 10Darline Graham, With Push From Trump, Wins Senate...nytimes.com

8. How did the actual turnout of 368,723 votes square with pre-election forecasts from major South Carolina political analysts?

Actual Turnout368,723 ballots cast (August 25, 2026, SC Republican Senate special primary runoff) [1][2][3][4]
Pre-election Consensus ForecastNot widely reported or available [3]
Specific Analyst ForecastNot found [5]
South Carolina's special primary runoff saw 368,723 votes cast. The official turnout for the August 25, 2026, South Carolina Republican Senate special primary runoff was reported as 368,723 ballots cast [1][2][3][4]. This figure represents the total number of votes submitted in that specific election.
No pre-election turnout forecasts were identified for comparison. Research did not find any widely reported pre-election consensus or specific forecasts from major political analysts regarding turnout figures for this special primary runoff [3][5]. Consequently, there is no basis to determine a significant discrepancy between analyst expectations and the actual results, as no such forecasts were identified [3].
Sources (5)
  1. 1South Carolina U.S. Senate Special Runoff Election Resultsnytimes.com
  2. 2U.S. Senate special GOP primary runoff: See the resultsgreenvilleonline.com
  3. 3U.S. Senate special GOP primary runoff: See the resultsyahoo.com
  4. 42026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  5. 52026 South Carolina US Senate Marketsvotes.decisiondeskhq.com

9. What were the key get-out-the-vote (GOTV) initiatives implemented by the Graham and Norman campaigns ahead of the August 25 runoff?

Super PAC Investment for Graham$827,000 [1][2][3]
Trump Tele-rally Duration20 minutes [2]
GOP Senate Runoff DateAugust 25, 2026 [1]
Ahead of the August 25, 2026, GOP Senate runoff, Darline Graham's campaign leveraged significant external support for voter mobilization. Her get-out-the-vote (GOTV) initiatives received substantial backing from the pro-Trump super PAC, MAGA Inc., which contributed approximately $827,000 towards targeted text message blasts and phone calls [1][2][3]. Former President Donald Trump also actively campaigned for Graham, holding an in-person rally in Myrtle Beach and conducting a 20-minute tele-rally on August 24, 2026, to urge his supporters to vote for her [2].
Conversely, Ralph Norman's campaign concentrated on direct in-person engagement with voters. His GOTV strategy emphasized direct appearances and organizing events with pastors, particularly within Greenville County—the state's most populous county—to energize and mobilize voters [1][4].
Sources (4)
  1. 1Darline Graham, Ralph Norman wrap up South Carolina Senate primary campaign | AP Newsapnews.com
  2. 2Trump makes final pitch for Darline Graham in South Carolina runoffusatoday.com
  3. 3MAGA Inc. spends $827,000 to back Darline Graham on final day of South Carolina GOP Senate runoffaudacy.com
  4. 4Graham, Norman make final pitches before GOP Senate runoff | WFAE 90.7 - Charlotte's NPR News Sourcewfae.org

10. What Could Change the Odds

Key Catalysts

Prediction markets during the South Carolina Republican Senate special election process were driven by several catalysts. These included candidate endorsements, notably from Donald Trump and other establishment figures [1][2][3]. Early and absentee voting trends also influenced market behavior [1]. The absence of credible public head-to-head polling contributed to significant price volatility [1][2][3].
The special primary election process was triggered by the death of incumbent U.S. Senator Lindsey Graham on July 11, 2026 [4][5][6]. This necessitated an initial primary on August 11, 2026, and a runoff on August 25, 2026 [7][8][9][4]. Early voting for the runoff occurred from August 19-21, 2026 [10][7]. Interim Senator Darline Graham won the August 25, 2026, runoff, defeating Ralph Norman with 52.45% (193,396 votes) to 47.55% (175,327 votes) [11][12][13][14]. Voter turnout for the runoff totaled 368,723 votes, with 63,712 early ballots cast statewide [10][15][13]. This turnout was approximately 3.5% higher than the initial primary on August 11, 2026 [15]. The general election is scheduled for November 6, 2026 [7][8][9].

Key Dates & Catalysts

  • Expiration: August 25, 2027
  • Closes: August 25, 2027
Sources (15)
  1. 1South Carolina Senate Primary Odds: Model Verdict | OddsShopperoddsshopper.com
  2. 2Two Races, One Seat: How Prediction Markets Are Pricing the South Carolina Senate Scramble - Prediction Authoritypredictionauthority.com
  3. 3South Carolina Senate Odds: Graham and the Special Primary | OddsShopperoddsshopper.com
  4. 4Primary runoff will determine Lindsey Graham's (R)...news.ballotpedia.org
  5. 5Primary election report notice - South Carolina Republican...fec.gov
  6. 6South Carolina and Maine will be the first states to replace a major party U.S. Senate nominee since 2016 - Ballotpedia Newsnews.ballotpedia.org
  7. 7Prep for the 2026 Special Republican Primary Runoffscvotes.gov
  8. 8SC Republican runoff election: Candidates, dates, polling spots | Myrtle Beach Sun Newsmyrtlebeachonline.com
  9. 9Special GOP Senate primary runoff: Everything South Carolina voters need to knowwbtv.com
  10. 10Early voting wraps up in South Carolina’s Republican U.S. Senate runofflive5news.com
  11. 11South Carolina U.S. Senate Special Runoff Election Resultsnytimes.com
  12. 12Sen. Darline Graham wins SC GOP Senate runoffgreenvilleonline.com
  13. 132026 South Carolina US Senate | Live Election Resultsvotes.decisiondeskhq.com
  14. 14United States Senate election in South Carolina, 2026ballotpedia.org
  15. 15High Early Turnout Raises Stakes in Tight South Carolina Senate Runoff - CRBC Newscrbcnews.com

12. Historical Resolutions

Historical Resolutions: 20 markets in this series

Outcomes: 13 resolved YES, 7 resolved NO

Recent resolutions:

  • KXPRIMARYTURNOUT-SENATEMID26-1600000: NO (Aug 25, 2026)
  • KXPRIMARYTURNOUT-SENATEMID26-1500000: YES (Aug 25, 2026)
  • KXPRIMARYTURNOUT-SENATEMID26-1400000: YES (Aug 25, 2026)
  • KXPRIMARYTURNOUT-SENATEMID26-1300000: YES (Aug 25, 2026)
  • KXPRIMARYTURNOUT-NY13D26-85000: NO (Jul 20, 2026)