Republican Senate Primaries Combo: Hold at 50¢

April 8, 2026 · By Tyler James Webber

The Kalshi Republican Senate primaries combo market trades at 50 cents with a YES fair value of 47-49%. Six candidates across Louisiana, Alabama, Georgia, Kentucky, Texas, and Minnesota divide into a strong block and a genuinely contested block. No actionable edge at current prices — full attention on May 16 and May 26.

Position. HOLD. Market mid at 50 cents (YES fair value 47-49%, range 30%-70%).

Edge. Flat. No actionable edge at current prices. Entry levels contingent on May 16 and May 26 outcomes.

Conviction. 4/10 (data quality 6/10, model confidence 5/10, completeness 7/10). The data quality is adequate across five of the six legs, where 270toWin aggregates and multiple independent polls are available. The Minnesota leg has no Republican primary polling and rests on structural inference. Model confidence is moderate because the fair value sits within the current bid-ask spread, leaving the position sensitive to small revisions. Completeness is solid, with all six legs tracked through the most current available data.

Key Dates. May 16 (LA primary), May 19 (AL, GA, KY primaries), May 26 (TX runoff), June 16 (AL, GA runoffs), June 27 (LA runoff), August 11 (MN primary).

Volume. Approximately $25,000.

Resolution. November 3, 2026, or when two of the named candidates lose their respective primaries.

Sizing. No position today. Full attention on May 16 (Louisiana) and May 26 (Texas).

The contract asks whether at least five of six named Republican Senate primary candidates will win their respective 2026 primaries. The candidates are Julia Letlow (LA), Barry Moore (AL), Mike Collins (GA), Andy Barr (KY), Ken Paxton (TX), and Michele Tafoya (MN). The market trades at approximately 50 cents mid as of April 7, 2026, with approximately $25,000 in volume. It resolves on November 3, 2026, or when two of the named candidates lose their respective primaries.

The six legs divide into two distinct groups by probability and evidence quality. Three are strong favorites: Collins in Georgia leads by 19.6 points across three independent surveys; Moore in Alabama holds a Trump endorsement and a polling advantage backed by 91% of all GOP primary television spending; Tafoya in Minnesota has no Republican primary challenger of consequence and NRSC backing. The remaining three are genuine contests: Paxton in a May 26 runoff against a well-funded incumbent, Barr in a no-runoff Kentucky primary where the RealClearPolitics average shows a statistical tie with Cameron, and Letlow in Louisiana where three independent polls show a true three-way race with no clear leader. The six primaries resolve across five separate dates between May 16 and August 11.

The market has moved from approximately 30 cents at open in February to the current 50 cents. That trajectory is rational. The Texas March 3 primary confirmed Paxton's advancement to the runoff, and independent polling solidified for Collins and Moore. The question is whether 50 cents correctly prices the remaining structure.

The six legs divide naturally into a strong block and a contested block. The strong block (Tafoya at 88%, Collins at 80%, Moore at 70%) has a combined probability of all three winning of 49.3%. The probability that at least two of the three win is 89.4%; only the tail scenario in which two strong-block leaders fail simultaneously threatens the YES condition, and current polling does not support that outcome. The contested block (Paxton at 67%, Barr at 63%, Letlow at 60%) has a combined probability of all three winning of 25.3% and a probability that at least two win of 69.6%. For the combo to resolve YES, the strong block must mostly hold, and the contested block must mostly hold simultaneously. The market at 50 cents is pricing that combined probability approximately correctly.

The crowd has recognized that this market is different from the Democratic primary combo. That market featured five candidates with individual probabilities ranging from 30% to 65%, producing 53 points of mispricing. Here, the bimodal structure, with three candidates well above 70% and three clustered at 60-67%, means the crowd's intuitive assessment lands close to the independent math. The mispricing, if any, is narrow.

The methodology is a candidate-by-candidate probability assessment, aggregated through the combinatorial constraint that at most one of the six named candidates may lose. Candidates are presented in primary date order.

Julia Letlow, Louisiana. 60%. The Louisiana Republican primary is May 16, with a runoff on June 27. Trump endorsed Letlow on January 18; Governor Landry also endorsed her. Cassidy voted to convict Trump in his 2021 impeachment trial and is the only Republican senator Trump's team is explicitly targeting for defeat this cycle. Three independent polls are available. Quantus Insights (February 23-24, 1,428 likely voters, ±2.8%) shows Fleming at 34%, Letlow at 25%, and Cassidy at 20%. BDPC (February 21-23, 600 likely voters), a bipartisan Louisiana firm, shows Cassidy at 28%, with Letlow and Fleming each at 21%. American Pulse (March 20-24, 455 likely voters, ±4.6%) shows Letlow at 31%, Fleming at 25%, and Cassidy at 21%. The three-poll average has Fleming at 26.7%, Letlow at 25.7%, and Cassidy at 23.0%, effectively a three-way race. The trend between the Quantus and American Pulse surveys favors Letlow, who rose six points while Fleming fell nine. American Pulse runoff simulations show Letlow beating Cassidy 54-24 and leading Fleming 37-34, the latter described by the pollster as too close to call. The probability chain: approximately 75% chance Letlow advances to the runoff, multiplied by a conditional runoff win probability of approximately 76% (weighted between a strong matchup against Cassidy and a near-coinflip against Fleming), plus a small probability of winning outright. Letlow's probability is approximately 60%.

Barry Moore, Alabama. 70%. The Alabama Republican primary is May 19, with a runoff on June 16. Trump endorsed Moore on January 17, 2026. The three most recent independent polls average Moore at 23.7%, Marshall at 19.3%, and Hudson at 15.0%: American Pulse (April 3, 505 likely voters, ±4.4%) shows Moore at 26%, Marshall at 21%, Hudson at 14%; the Alabama Poll (March 30, 600 likely voters, ±4.0%) shows Moore at 23%, Marshall at 21%, Hudson at 19%; and Remington Research (March 2-4, 692 likely voters, ±3.7%) shows Moore at 22%, Marshall at 16%, Hudson at 12%. The RealClearPolitics average, which incorporates a broader set of polls including older surveys when Marshall polled higher, shows Marshall at 23.5% and Moore at 18.0%. The two aggregators reach opposite conclusions, but the discrepancy is explained by methodology rather than genuine ambiguity: RCP incorporates older surveys from a period before Moore's $4.7 million advertising campaign reached voters, when Marshall polled higher. Recency-weighted aggregation is more defensible in a race with visible momentum and a documented spending asymmetry of 91% to 9%, and the three most recent independent surveys are the more reliable signal. Approximately $4.7 million in pro-Moore advertising represents 91% of all GOP primary television spending, with $4.5 million from the Defend American Jobs PAC. The Alabama Poll's geographic crosstabs show Marshall with favorability advantages in media markets covering roughly 78% of the likely primary electorate, though Hudson's momentum appears to have stalled in the April survey. A majority-threshold runoff on June 16 is near-certain. Moore's probability is approximately 70%.

Mike Collins, Georgia. 80%. The Georgia Republican primary is May 19, with a runoff on June 16. The 270toWin three-poll average has Collins at 32.3%, Carter at 12.7%, and Dooley at 10.7%, a 19.6-point lead. Quantus Insights from February 19 (1,337 likely voters, ±3.0%) showed Collins at 36%. Emerson College from March 5 (453 likely voters) showed Collins 30%, Carter 16%, Dooley 10%. JMC Analytics from March 9 (560 likely voters) showed Collins 31%, Carter 11%, Dooley 13%. Trump has not endorsed any Georgia candidate; Governor Kemp endorsed Dooley, who has not moved into contention in any independent survey. A majority-threshold runoff is near-certain; Collins's structural advantage in a two-candidate contest is substantial, given the first-round margin. Collins's probability is approximately 80%.

Andy Barr, Kentucky. 63%. The Kentucky Republican primary is May 19, with no runoff; the plurality winner takes the nomination. The most recent independent poll is Emerson College (March 29-31, approximately 549 likely Republican voters, ±4.1%), showing Barr at 28%, Cameron at 21%, Morris at 15%, with 29% undecided. The RealClearPolitics average shows Barr at 26% and Cameron at 24%, a two-point gap within any poll's margin of error. The Quantus Insights survey from February 5 (870 likely voters, ±3.3%) had Barr at 28% and Cameron at 27%, essentially tied. Trump has not endorsed any candidate; at a March event in Kentucky, he praised all three without committing. Barr chaired Trump's 2024 Kentucky reelection campaign; Cameron was the first Kentucky statewide official to endorse Trump in January 2023. A Trump endorsement for Cameron would likely flip the no-runoff primary, given the current statistical tie. Among undecideds, the 29% figure in the March Emerson survey is the most consequential unresolved variable. In no-runoff primaries with high undecideds, late deciders typically break toward name recognition and organizational depth rather than ideological positioning alone. Barr's statewide profile, built across multiple House terms and the chairmanship of Trump's 2024 Kentucky reelection campaign, gives him a structural advantage over Cameron, whose statewide recognition derives primarily from his 2023 gubernatorial loss. That structural edge supports a modest Barr lead over the polling average, and is reflected in the 63% estimate.

Ken Paxton, Texas. 67%. The Texas Republican primary runoff is on May 26. Paxton advanced after the March 3 primary, which produced 41.9% for Cornyn and 40.7% for Paxton, with Hunt finishing a distant third. Five runoff surveys are available. GQR (March 30, 600 likely voters): Paxton 47, Cornyn 42. Quantus Insights (March 24, 1,218 likely voters): Paxton 49, Cornyn 41. Change Research (March 19, 811 registered voters): Paxton 42, Cornyn 39. Public Policy Polling (March 13, 565 likely voters): Paxton 45, Cornyn 42. Texas Public Opinion Research (March 9, 781 likely voters): Paxton 49, Cornyn 41. The five-poll average is Paxton at 46.4% and Cornyn at 41.0%. Runoff electorates skew toward the MAGA base, Paxton's core constituency. Cornyn edged Paxton in first-round actual returns (41.9-40.7), indicating a persistent polling premium that has not materialized on Election Day; a two-to-three-point discount reduces the adjusted margin to approximately +2.5-4 points. Pro-Cornyn groups have outspent Paxton approximately 75:1 since March 3 ($2.2 million to under $30,000). Trump has not endorsed either candidate five weeks after the primary. Change Research data shows a Cornyn endorsement would swing the race from Paxton +3 to Cornyn +3. Paxton's probability is approximately 67%.

Michele Tafoya, Minnesota. 88%. The Minnesota Republican primary is on August 11. No independent public polling of the Republican primary exists. The NRSC endorsed Tafoya immediately upon her entry in January 2026, clearing the field of credible challengers. A Peak Insights internal survey from February showed Tafoya leading the field by approximately 30 points; Royce White, the party's 2024 nominee who won that year's primary with approximately 38% of the vote despite holding the convention endorsement, is a distant second. The state Republican convention in late May introduces a minor procedural risk: Tafoya's past call urging Trump not to run in 2024 and her self-described pro-choice position may cost her the party's formal endorsement, but convention-endorsed candidates can and do lose primaries in Minnesota. Tafoya's probability is approximately 88%.

Aggregation. The combo requires at least five of six to win. The six legs divide into a strong block (Tafoya at 88%, Collins at 80%, Moore at 70%, with P(all three win) = 49.3%) and a contested block (Paxton at 67%, Barr at 63%, Letlow at 60%, with P(at least two of three win) = 69.6%). The mechanical calculation is:

P(all 6 win) = 0.88 × 0.80 × 0.70 × 0.67 × 0.63 × 0.60 = 0.1248 (~12%)

P(exactly 5 win) = 0.3197 (~32%)

P(at least 5 of 6 win) = 0.3197 + 0.1248 = 0.4445 (~44%)

The Change Research data in the Texas section quantifies the effect of a Trump endorsement on a contested leg: a six-point swing, moving the race from Paxton plus three to Cornyn plus three. Applying the same logic to Kentucky, where a Cameron endorsement likely resolves a statistical tie, implies a shift of roughly 10 to 15 points for Barr. Louisiana's Trump endorsement is already incorporated in Letlow's 60% estimate. The positive correlation scenario requires Trump to endorse Paxton before May 26 and Barr before May 19, neither of which has happened five weeks into the runoff window. Assigning 25% probability to a Paxton endorsement (worth roughly six points on that leg) and 20% probability to a Barr endorsement (worth roughly 10 points on that leg), the expected value of the endorsement shock is approximately 1.5 points on Texas and two points on Kentucky, which translates to roughly two percentage points at the combo level after running through the combinatorial math. That is the source of the two-point correlation adjustment, yielding a central estimate of 47%. At the high end of the endorsement scenario, 49%.

The range of 30-70% reflects the following. The low end (30%) corresponds to a scenario in which all three contested legs underperform their assessed probabilities by approximately 15 percentage points, treating Paxton as a 52% favorite, Barr as a 48% favorite, and Letlow as a 45% favorite. The high end (70%) corresponds to upward adjustments of approximately 20 percentage points on each contested leg, consistent with a Trump endorsement sweep across the unendorsed races.

Contested leg sensitivity analysis. "Which way does the position break if the three contested probabilities are wrong?" The table below shifts the three contested legs (Paxton, Barr, Letlow) simultaneously while holding Tafoya, Collins, and Moore at their assessed values. These three legs are where the model risk is concentrated; the strong-block candidates lead by margins wide enough that systematic misestimation is implausible.

| Shift | Paxton | Barr | Letlow | Combo FV | Edge vs. 50¢ | Position | |-------|--------|------|--------|----------|--------------|----------| | −20pp | 47% | 43% | 40% | ~23% | +27pp | BUY NO | | −10pp | 57% | 53% | 50% | ~33% | +17pp | BUY NO | | Base | 67% | 63% | 60% | ~44% | +6pp | HOLD | | +10pp | 77% | 73% | 70% | ~56% | −6pp | BUY YES | | +20pp | 87% | 83% | 80% | ~69% | −19pp | BUY YES |

The table shows that the market is priced near the center of the plausible range for the contested legs. At base, the edge for either direction is approximately six points, thin enough to represent noise rather than signal. A minus-10-point shift, treating Paxton as a 57% favorite and Letlow as a 50% favorite, produces 17 points of BUY NO edge. A plus-10-point shift, consistent with a Trump endorsement of Barr and active reinforcement of Paxton and Letlow, produces six points of BUY YES edge. Neither scenario requires catastrophic model error; both are within the range of plausible polling movement or endorsement-driven change.

The asymmetry is informative: the downside scenarios (BUY NO territory) are more probable than the upside scenarios (BUY YES territory), given the current absence of Trump endorsements for all three contested legs. But the edge in either direction is modest until a triggering event resolves.

A Trump endorsement of Cornyn in Texas before May 26 is the single highest-impact event. A Cornyn endorsement drops the Texas leg from 67% to approximately 42%, pushing YES fair value toward 35% and creating a compelling BUY NO entry. A Paxton endorsement lifts the Texas leg toward 78% and pushes fair value above 50%, creating a BUY YES entry.

A Letlow first-round failure in Louisiana on May 16 is the second most consequential event for YES holders. If Letlow finishes third and the June 27 runoff proceeds between Fleming and Cassidy, the combo requires all five remaining candidates to win. YES fair value collapses to approximately 21% against a 50-cent market.

A Trump endorsement of Cameron in Kentucky before May 19 would likely flip the no-runoff primary, given the current statistical tie, removing that leg from the YES column and pushing YES fair value to approximately 20%, consistent with the other single-leg elimination scenarios.

The multi-round structure of the Alabama and Georgia primaries introduces a two-stage risk not present in the Democratic combo. Moore and Collins must first advance to their June 16 runoffs and then win them. The current probabilities incorporate both stages, but a Hudson first-round surprise in Alabama or a Carter late surge in Georgia would reset the analysis at the runoff stage in ways the current model cannot price.

Louisiana primary, May 16. The first leg to resolve and the most informative near-term event. A Letlow runoff advancement preserves the probability structure. A first-round Letlow failure collapses YES fair value to approximately 21%, making BUY NO immediately actionable.

Alabama, Georgia, Kentucky primaries, May 19. Three legs resolving simultaneously. If Moore and Collins advance to their respective runoffs and Barr wins outright, YES fair value moves toward 55-58% with only the two June runoffs and Texas remaining. Any single miss on May 19 is sharply negative for YES.

Texas runoff, May 26. The pivotal event. A Paxton win pushes YES fair value toward 57-60%, with only the June runoffs and Minnesota remaining. A Cornyn win requires all five remaining candidates to win, collapsing YES fair value to approximately 19%. The asymmetry is unfavorable for YES holders: a Paxton win adds roughly 10 points while a Cornyn win subtracts roughly 28 points from the 47% adjusted baseline.

Alabama and Georgia runoffs, June 16. Secondary resolution events. Both Moore and Collins are expected runoff favorites. Informational rather than repricing events absent a surprise on May 19.

Trump endorsement timeline. Any endorsement in Texas or Kentucky creates immediate directional clarity. The single most important unobservable variable in this market.

HOLD at current prices. The market has a 47-49% fair value against a 50-cent market; edge is approximately -2 to +2 percentage points. Conviction is 4/10.

The Democratic primary combo, analyzed earlier in the cycle, had a 14% fair value against a 67-cent market: 53 points of mispricing, with the BUY NO position holding through a plus-25-point uniform shift across all five candidates. This market has a 47-49% fair value against a 50-cent market: approximately zero mispricing. The contested-leg sensitivity table shows the position tips to BUY YES with only a plus-10-point shift in the three uncertain legs, a level of movement that represents endorsement news, not model failure. A fairly priced market waiting for two events to resolve.

Two events in the next seven weeks will determine whether a position is warranted. Until they resolve, no size is appropriate on either side.

If Cornyn wins the May 26 Texas runoff, YES fair value drops to approximately 19% against a market that will lag the result. If Letlow fails to advance in Louisiana on May 16, YES fair value drops to approximately 21%. BUY NO at 35-40 cents in either scenario represents 10-15 points of edge, with a position that holds unless every remaining candidate overperforms by a wide margin simultaneously.

If Paxton wins on May 26, Letlow advances on May 16, and the three May 19 primaries all produce expected outcomes, YES fair value rises to approximately 57-60% with only the June runoffs and Minnesota remaining. BUY YES below 53 cents in that scenario.

No position today. Full attention on May 16 and May 26.