Next SCOTUS Vacancy

Supreme Court vacancy markets are built to reprice on a retirement report, and for most of the year they sat untraded. That has changed at the edges: the page turned $11,887 in a day, led by $6,109 on Kalshi's confirmation ladder and $4,238 on its certiorari board. The two personnel books at the center are still quiet: $27 on the next-justice field and nothing on the resignation board.

Samuel Alito remains the market's answer to who leaves first: 58% on Kalshi's resignation board, 63.9% and 60.8% on Manifold's two community books. Clarence Thomas is second on all three.

The replacement field now has a leader. Andrew Oldham is 23% on Kalshi's next-justice book, ten points clear of James Ho at 13%. Three weeks ago the two were level at about 14%.

Two dated ladders on when a seat opens and is filled. In September both carried pricing artifacts: a wider window priced below a narrower one, and a leg anchored to a date already past. Both are gone.

New justice confirmed: 6.9% before 2027, 17.5% before June 2027, 41.5% before 2028 and 56% before January 21, 2029. The nearest leg took $5,903 of the book's $6,109.

Alito's retirement: 8.15% before January 1, 2027 and 27% before July 1, 2027, on $812.

One tension remains. Kalshi prices Alito resigning during the term at 58% and any new justice being confirmed before January 21, 2029 at 56%. The second can sit below the first only if a late vacancy goes unfilled before the term ends.

Two adjacent books that price what the Court does rather than who sits on it. Whether the Court overturns Obergefell before 2029 is 10.55%, up from 7.3% three weeks ago, on $701. Beside it, the certiorari board on which cases the Court agrees to hear in 2026: Roybal v. Griffith 33%, Norfolk Southern Railway v. Mallory 32.5%, Bird v. Iowa Migrant Movement for Justice 32%, U.S. DOGE Service v. U.S. District Court 31.5% and Republican National Committee v. Eakin 24%. Mallory was 65% in September and Eakin 47.5%; the board turned $4,238.

Kalshi's Categorical on who the next Supreme Court justice is. Andrew Oldham leads at 23%, then James Ho at 13%, Aileen Cannon at 6.95%, Amul Thapar at 6.05% and D. John Sauer at 5.5%. In September Ho and Oldham were level near 14% and the field read as flat; Oldham has since pulled ten points clear, on a book that turned $27 today. Beside it, Kalshi's resignation board: Alito 58%, Thomas 48.5%, then John Roberts at 19%, Sonia Sotomayor at 9.5% and Amy Coney Barrett at 5%, each leg priced on its own.

Manifold's two community forecasts on which sitting justice departs first. Both agree with Kalshi's order: Alito at 63.9% and 60.8%, Thomas at 26% and 28.9%, and nobody else above about 4%.

Kalshi's resignation board is not a single-winner book, so its legs do not sum: Alito at 58% and Thomas at 48.5% together say the market expects at least one, and quite possibly both, of the Court's two oldest members to go before January 2029.

• Alito, then Thomas, then nobody. Three books on two exchanges price the same order. Cross-exchange agreement on an untraded question is worth more than any single quote.
• Oldham at 23%. The replacement field was flat in September; it now has a ten-point leader. The move came on almost no volume, so read it as a quote more than a consensus.
• The near legs are where the money is. $5,903 on confirmed before 2027 at 6.9% and $646 on Alito before January 1, 2027 at 8.15%. Both settle in three months.
• Obergefell at 10.55%. Up three points in three weeks.
• The cert board has halved its September leaders. Mallory from 65% to 32.5%, Eakin from 47.5% to 24%. The Court's new term opens Monday, October 5.
• The trigger: any health or retirement report on Alito or Thomas is the event this whole stack exists to reprice on.