Next SCOTUS Vacancy

Supreme Court vacancy markets are the clearest example in the catalog of a book that is structurally important and almost entirely untraded. Nothing here turns over more than $603 in a day. They exist to reprice instantly on a retirement rumor, and until one arrives the quotes are best read as a standing shortlist rather than a live consensus.

Two things have stayed stable across every look at this workspace. Samuel Alito is the market's answer to who leaves first—58.5% on Kalshi's resignation Multiple, 64.1% and 68.3% on Manifold's two community books. And the replacement field is genuinely flat: James Ho at 14.5% and Andrew Oldham at 14% lead a list where the tenth name still prices above 2%.

This workspace also collects three pricing artifacts that are worth seeing precisely because the books are thin—see the section below.

Three artifacts of an illiquid book, kept here deliberately because they are instructive.

One: a cumulative that runs backwards. The New Supreme Court justice confirmed? Multiple prices Before 2028 at 74.5% and Before Jan 21, 2029 at 42.5%. A wider window cannot be less likely than a narrower one inside it. This is not a view; it is two legs that have not traded against each other.

Two: a leg anchored to a date in the past. The Alito timing Multiple still shows Before Jul 1, 2026 at 50%—a question that resolved six weeks ago, sitting at the untraded default.

Three: volume on the wrong rungs. On that same book, $163 sits on Before Jan 1, 2027 (5.4%) and $90 on Before Sep 1, 2026 (0.3%), while the leg that actually matters carries nothing. When reading any thin book, check whether the money is where the probability is. Here it is not.

Two adjacent books that price what a vacancy would be for, rather than when it happens. Whether the Court overturns Obergefell before 2029 sits at 7.3%, and it is the second-deepest book in this workspace at $462—more flow than the replacement Categorical itself. Alongside, the certiorari Multiple on which cases the Court agrees to hear in 2026, led by Norfolk Southern Railway v. Mallory at 65% and Republican National Committee v. Eakin at 47.5%. The cert book is the only market here that resolves on Court action rather than on a personnel event.

Kalshi's Categorical on who the next Supreme Court justice is—the market's read on the Administration's shortlist. Two Fifth Circuit judges lead: James Ho at 14.5% and Andrew Oldham at 14%, with Amul Thapar at 9% and Aileen Cannon at 7.7%. Note the composition: the top of the list is appellate judges, but Ron DeSantis at 5% and Ted Cruz at 3.2% both price above several sitting circuit judges. The field is a mix of conventional judicial picks and political ones, and the book does not strongly separate them.

Manifold's two community forecasts on which sitting justice departs first, next to Kalshi's own resignation Multiple. All three agree, and they agree strongly: Alito, then Thomas, then a very long gap. Manifold has Alito at 64.1% and 68.3% across its two differently-worded books; Kalshi's Multiple prices Alito resigns during this term at 58.5% and Thomas at 50%.

Kalshi's is a Multiple, so the legs do not sum—58.5% and 50% together are a statement that the market expects at least one and quite possibly two of the Court's two oldest members to go before January 2029.

• Alito, then Thomas, then nobody. Three books on two exchanges, all independently pricing the same order with the same steep drop after the second name. Cross-exchange agreement on a thin question is worth more than any single quote.
• The replacement field is flat and mixed. Ho 14.5%, Oldham 14%, Thapar 9%. No consensus pick, and elected politicians priced alongside circuit judges.
• Nothing here is liquid. The deepest book in the workspace turns over $603 a day. These are watchlist quotes, not consensus prices—which is exactly why the arbitrage-free violations survive.
• A cumulative running backwards is the tell. Before 2028 at 74.5% against Before Jan 21, 2029 at 42.5% is arithmetically impossible and has stood uncorrected. In a liquid book this closes in minutes.
• Obergefell at 7.3% is the sleeper. More money on that single contract than on the entire next-justice Categorical.
• What to watch: any health or retirement report on Alito or Thomas, which is the event this whole stack exists to reprice on, and whether the confirmation-timing legs ever get arbitraged back into order.