Kalshi KXSCOTUS: Supreme Court case outcomes — order book & trade data
22.0K book and trade events for Kalshi's supreme court case outcomes markets, recorded live since 2026-10-01 — about 880 events a day.
Coverage
KXSCOTUS Supreme Court data coverage
What is recorded, how often it updates and how much there is.
Recording since
2026-10-01
25 days so far · no backfill
Events recorded
22,000
≈ 22.0K as of 2026-10-25
Avg events / day
880
book snapshot · book delta · trade
Update frequency
Order-book snapshots, deltas and trades streamed in real time
Daily activity · last 25 days
Indicative daily event volume, last 25 days to 2026-10-25. Shape modeled from collector stats; mean matches the average events/day above.
About this market
What is KXSCOTUS Supreme Court?
KXSCOTUS prices binary outcomes on major Supreme Court cases — thin markets that stay quiet for months and then trade hard when oral arguments or opinions land. AymarData has been recording the KXSCOTUS series since 2026-10-01 and holds 22.0K events so far — about 880 a day. History is forward-only; we record live and do not backfill Kalshi.
Participants are specialists: legal analysts, political desks and prediction-market regulars. Spreads are wider than Fed contracts, and a single opinion day can produce most of a month's events.
Treat KXSCOTUS as an event series: filter to argument and opinion dates, then study how the book thins before the decision and how quickly it converges afterward.
What moves KXSCOTUS
- Oral-argument transcripts and live commentary
- Leaked or rumoured vote counts ahead of opinions
- The published opinion, which settles the contract
Schema
KXSCOTUS Supreme Court fields and sample rows
The same columns are returned by the API and in Parquet and CSV files.
| Field | Type | Description |
|---|---|---|
| ts_ms | int64 | Exchange event time, Unix milliseconds |
| ticker | string | Full Kalshi market ticker |
| event_type | string | book_snapshot | book_delta | trade |
| side | string | buy / sell on trades; bid / ask on book events |
| yes_bid | number | Best YES bid, 0–1 dollars |
| yes_ask | number | Best YES ask, 0–1 dollars |
| volume | int64 | Contracts traded or resting at the level |
Sample rows
| ts_ms | ticker | event_type | side | yes_bid | yes_ask | volume |
|---|---|---|---|---|---|---|
| 1792505404981 | KXSCOTUS-26OCT-AFFIRM | book_snapshot | bid | 0.55 | 0.6 | 3152 |
| 1792505405700 | KXSCOTUS-26NOV-REVERSE | trade | buy | 0.33 | 0.38 | 2264 |
| 1792505407357 | KXSCOTUS-27JAN-DISMISS | book_delta | ask | 0.12 | 0.17 | 2214 |
Illustrative rows for the KXSCOTUS series; tickers follow Kalshi's naming and prices are YES quotes in dollars (0–1).
Code
Pull KXSCOTUS Supreme Court in Python, cURL or MCP
Market id: KXSCOTUS-26OCT-AFFIRM. Export AYMARDATA_API_KEY from your dashboard, then run the Python requests example.
import os
import requests
API = "https://api.aymardata.com/v1"
KEY = os.environ["AYMARDATA_API_KEY"] # export AYMARDATA_API_KEY=ad_live_…
H = {"Authorization": f"Bearer {KEY}", "User-Agent": "aymardata-docs/1.0"}
# KXSCOTUS: ten minutes of trades and book updates for one contract
trades = requests.get(
f"{API}/trades",
headers=H,
params={
"source": "kalshi",
"market": "KXSCOTUS-26OCT-AFFIRM",
"start": "2026-10-20T14:00:00Z",
"end": "2026-10-20T14:20:00Z",
"limit": 500,
},
timeout=30,
).json()["data"]
last = trades[-1]
print(last["ticker"], last["yes_bid"], last["yes_ask"])
book = requests.get(
f"{API}/book",
headers=H,
params={
"source": "kalshi",
"market": "KXSCOTUS-26OCT-AFFIRM",
"at": "2026-10-20T14:10:00Z",
"depth": 10,
},
timeout=30,
).json()
print(book.get("spread"), len(trades))FAQ
KXSCOTUS Supreme Court: common questions
Why are event counts low most days?
Cases last months and only a few calendar days matter. Between arguments and opinions the tape is sparse by design.
How do tickers identify a case?
They usually include a short case label and outcome side. Confirm the exact question text in the contract rules — settlement language is legal, not political shorthand.
What moves KXSCOTUS prices?
Oral-argument transcripts and live commentary; leaked or rumoured vote counts ahead of opinions; and the published opinion, which settles the contract.
How much KXSCOTUS history is available?
Recording began 2026-10-01 and is forward-only. At the time of this page that is 25 days, 22.0K events and about 880 events a day.
How do I query KXSCOTUS data with the API?
Use market=<full ticker> such as KXSCOTUS-26OCT-AFFIRM with source=kalshi on /v1/trades or /v1/book, or ask the MCP server for the series by name. The snippets on this page are ready to run with your API key.
Backtest KXSCOTUS Supreme Court with real tick data
Get an API key, pull your first window and join it with the other sources in the catalog.