When is the South Carolina Senate runoff? Tuesday, August 25, 2026, two weeks after the August 11 special Republican primary ended with nobody clearing the majority bar. But the date is only half the answer, because the market that has been pricing this race since primary night just changed its mind in a hurry. Overnight into Friday, Kalshi traders cut appointed Sen. Darline Graham Nordone from 80 cents to 70 and lifted U.S. Rep. Ralph Norman from 22 to 30, a mirrored move of roughly nine points on more than a million dollars of 24-hour volume. A runoff wipes a crowded board down to two names and restarts the race, and the price contains a live judgment about where the eliminated candidates' voters land. This week, that judgment moved. By the end of this page you'll be able to read it straight off two boards: the candidate market and, just as telling, the turnout market underneath it.
The Quick Answer
The South Carolina Senate special Republican primary runoff is Tuesday, August 25, 2026, between appointed Sen. Darline Graham Nordone and U.S. Rep. Ralph Norman. Early voting runs August 19-21; polls are open 7 a.m. to 7 p.m. on election day. Kalshi prices Graham Nordone at 70 cents (an implied 70% chance) and Norman at 30 cents as of the morning of August 21, 2026, after an overnight repricing that took roughly nine points off her price in the race's final week. Why the race went to a second vote, what moved the market, and how to read the turnout board as the tiebreaker are all below.
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Why August 25? South Carolina's Majority Rule
South Carolina primaries are not won by simply finishing first. Under the state's majority-vote rule, a candidate needs more than 50% of the vote to take the nomination outright; otherwise the top two finishers meet again two weeks later. The South Carolina Election Commission's special election schedule set that contingency date before a single vote was cast: primary on Tuesday, August 11, statewide runoff (if necessary) on Tuesday, August 25.
Necessary it was. The August 11 special primary to fill the late Sen. Lindsey Graham's seat drew a 10-candidate Republican field, and no one came close to the majority line. Graham Nordone led with 109,881 votes, just under a third of the ballots, to Norman's 82,627, about a quarter, which left more than 40% of the first-round vote with candidates who are now off the ballot entirely. That orphaned vote is the whole contest: whoever inherits more of it on the 25th wins the nomination, and the market has spent two weeks pricing exactly that question.
Who's In The Runoff: Graham Nordone Vs. Norman
Darline Graham Nordone is the appointed incumbent, sworn in this July to fill the seat of her late brother, Lindsey Graham, and the first woman ever to represent South Carolina in the U.S. Senate. She had never held elected office before Gov. Henry McMaster appointed her on President Trump's recommendation, which makes this runoff her first real test in front of voters.
Ralph Norman, the U.S. congressman and House Freedom Caucus member, finished second, ahead of fellow Rep. Russell Fry, taking the final runoff slot, with Fry near 20% and former Gov. Mark Sanford around 15%. Fry, Sanford and the rest of the field are out, and that word "out" matters for the market mechanics below: on Kalshi, elimination isn't just a news event, it's a settlement event.
The endorsement war over the leftovers has split the party's biggest names. Nikki Haley, Jim DeMint, and Sens. Rick Scott and Mike Lee lined up behind Norman; Sen. Tim Scott, Senate Majority Leader John Thune and Sen. Tom Cotton backed Graham Nordone, and Trump, who recommended her appointment, personally called Mark Sanford to ask him to endorse her. Norman's own Trump history is a live attack line here: a green energy PAC's ads have hit him for endorsing Haley over Trump in the 2024 presidential primary.
What Moved The Board: The Debate
The one scheduled debate of the runoff, held August 18 in Newberry, gave the race its defining moment. Asked about Taiwan and the South China Sea, Graham Nordone answered that "national security is not my thing" and said she is "not that informed on national security," then spent much of the night defending a résumé that includes no prior elected office. Norman pressed exactly there, attacking her inexperience and charging that her campaign is propped up by dark-money groups he tied to Democrats, a claim that is his campaign's framing rather than a settled fact, but one that landed in the room.
The timeline that mattersdebate on August 18, early voting August 19-21, and the overnight repricing into August 21 that cut Graham Nordone from 80 cents to 70. The market moved during the exact window when real ballots started banking.
Nobody can point to a single headline that moved the price on any given night, and it would be dishonest to try. What the price history shows is a sequence: the debate on the 18th, early voting opening on the 19th, and, with two days of early ballots banked, an overnight repricing into Friday morning that took Graham Nordone from 80 cents to 70. A board that stood at 80 moved nine points during the exact window when actual votes started locking in. That timing is the story.
The case for each side of the South Carolina (SC) Senate primary, priced on Kalshi: Why Ralph Norman Will Win The South Carolina Senate Primary · Kalshi Odds: Why Darline Graham Will Win The SC Senate Runoff · Why Darline Graham (R) Will Win South Carolina's Senate Race · Why Annie Andrews (D) Will Win South Carolina's Senate Race
The Live Two-Horse Board
Here is the runoff market (Kalshi ticker KXSCRSENS-26) as of the morning of August 21, 2026:
| Contract | Bid / Ask | Previous Price | 24-Hour Volume | Open Interest |
|---|---|---|---|---|
| Darline Graham Nordone To Win | 70¢ / 71¢ | 80¢ | $591,858 | 2.09M contracts |
| Ralph Norman To Win | 30¢ / 31¢ | 22¢ | $486,599 | 2.00M contracts |
The row worth staring at is Norman's. A move from 22 to 30 cents is not cosmetic; in implied-probability terms the market just raised his chance of winning the nomination by more than a third, in one overnight session, four days before the election. And the quality of the print backs it up: the two sides sum to roughly 1.01, the spreads are a single penny wide, and nearly $1.08 million changed hands across the pair in 24 hours on more than four million contracts of open interest. Thin markets gap around on stale quotes; this is the opposite, real money paying up to reprice a race in its final week. Graham Nordone at 70 is still a clear favorite, but 70 is a different claim than 80: the board has trimmed her implied chance by a meaningful bite while keeping her ahead.
For the deeper candidate-by-candidate modeling behind this race, our South Carolina Senate special election odds page tracks the runoff market in full, the primary's full price history shows how the first-round board resolved, and the 2026 midterm election odds hub carries every board this cycle. Newer to reading these markets? Start with whether prediction markets are actually accurate.
The Turnout Market Is The Tell
Remember the thesis: this runoff is a fight over the 40%-plus of first-round voters whose candidates are gone. How many of them show up decides who inherits them, and Kalshi trades that question directly. The first round drew 335,693 total ballots; runoffs usually shrink. Here is the turnout board (KXPRIMARYTURNOUT-SCRSENS26) as of the same August 21 snapshot:
| Runoff Turnout | Bid / Ask |
|---|---|
| Above 200,000 Ballots | 94¢ / 99¢ |
| Above 250,000 Ballots | 72¢ / 79¢ |
| Above 300,000 Ballots | 43¢ / 49¢ |
The line I keep coming back to is the 300,000 contract, bid 43 and asked at 49. That window straddles a coin flip on a runoff nearly matching the first round's 335,693 ballots, and the 72-79 window on 250,000-plus reads as roughly three-in-four likely. That is not what a sleepy, die-hards-only runoff looks like, and it matters because the two shapes of electorate favor different candidates. A collapsed-turnout runoff concentrates the vote among the most motivated partisans, the profile Norman's Freedom Caucus base fits; a broad electorate near first-round size looks more like the one that gave the appointed incumbent her first-round lead. So read the two boards together: Norman's price rising while the turnout market holds these levels says traders think the late energy, the debate clip and the banked early votes are breaking his way inside a big electorate, not just that his base will be the only one showing up. If the 300k contract fades toward 20 cents over the weekend while Graham Nordone climbs back toward 80, that read flips. The two boards are one instrument.
How Runoff Pricing Works On Kalshi
On this board, the mechanics and the race are the same sentence. Each survivor has a Yes contract that pays $1 on a win, so the price in cents reads directly as implied probability, and no house sets the number — traders set it against each other, a distinction we unpack in prediction market vs. sportsbook.
A Worked Example At The Live Prices
A buyer of Norman Yes today pays the 31-cent ask to collect $1.00 if he wins the nomination, a bit over three times the money. Strip the abstraction away and that 31 cents is a very specific claim: it's a bet that enough of the orphaned 40%-plus, the Fry and Sanford voters this whole runoff is fighting over, breaks toward the Freedom Caucus challenger over the appointed incumbent. A buyer of Graham Nordone pays 71 cents for the opposite claim on the same voters. Note that the fill happens at the ask, not the last trade, so the "one number" you see quoted is really a one-penny window here, and the two sides summing to about 1.01 is exactly what a coherent, liquid two-way market should look like.
Everyone else's contracts are already gone. When Fry was eliminated on primary night, his primary-market contract, like Sanford's and the rest, settled No at $0 once the first round was called, without waiting for August 25. That's the callback to "out" from earlier: a runoff market only ever carries the two survivors, and Kalshi typically settles once the result is called. Until then, prices move on endorsements, debate fallout and turnout signals, which is precisely what this week's tape shows.
Can You Vote In The Runoff?
Early voting for the runoff runs Wednesday, August 19 through Friday, August 21, 8:30 a.m. to 5 p.m., per the Election Commission's runoff schedule; election day polls run 7 a.m. to 7 p.m. on the 25th. The crossover rule catches people every cycle: per the Commission's voter reminders, voters who participated in the June Democratic primary are not eligible in this Republican contest; those who voted in the June Republican primary, or sat out both, are eligible. Bring a photo ID — a South Carolina driver's license, DMV ID card, photo voter registration card, military ID or passport all qualify. This rule feeds the market read from earlier: the eligible electorate is capped at people who could vote in the Republican special in the first place, so the turnout board is pricing engagement inside a fixed pool, not new voters discovering the race.
What Happens After August 25
The runoff winner becomes the Republican nominee and faces Democrat Annie Andrews, a pediatrician, in November's general election. Kalshi's November board priced the Republican side at 88 cents to Andrews' 11 as of this page's previous edition on August 12, 2026, and it carries a structural quirk: Andrews is listed by name, but the Republican side trades only as "Republican party," because Kalshi can't post a named contract for a nominee who doesn't exist yet. Until Tuesday settles, the 70-30 board is the only place to trade the "which Republican" question, and since the market treats the nomination as most of the ballgame in this seat, it's effectively pricing who South Carolina's next senator will be.
That's the story of this race in its final week: a majority rule forced a reset, the reset produced a two-name market, and after that market spent the runoff window backing the appointed incumbent as high as 80 cents, one debate answer and two days of banked early votes knocked the price to 70 while the turnout board says the electorate is showing up big. If following live election boards is your thing, the same read-the-price approach works across every race this cycle — start with our guide to when polls close and how markets react, and if you want the sharp side of the site while you're here, the free expert picks page is the no-cost way in. This page stays on this URL through the runoff; check back the morning of August 26 for the settled board.
The Candidates' Records, Briefly
Both names on this runoff ballot have public records worth knowing. Ralph Norman drew national coverage in 2018 for displaying a loaded handgun at a constituent meeting (CBS News; no charges), and in 2022 a federal judge dismissed him from a defamation lawsuit over a Facebook post (AP via NBC). Darline Graham has no documented lawsuit or ethics record; the sharpest attacks on her come from a FITSNews opposition file, which is attributed opinion, not record. The full sourced rundown is on the main runoff page.
More on this: 2026 Senate Races: Every Kalshi Board We Track · South Carolina Senate Runoff Turnout: The 375,000-Voter Question · Who Won The South Carolina Senate Runoff: Graham By 5 Points · Why Darline Graham (R) Will Win South Carolina's Senate Race · Trump Address To The Nation: 78% Chance Before Dec. 1
