RizonWhen will Anthropic’s shares start trading?
The market's forecast: Nov 20, 2026.
Anthropic IPO: date trades as a horizon contract: Higher or Lower on the number, paying a fixed 2× if it finishes on your side of the strike. The order book quotes the strike, so its midpoint is the market's forecast of the number itself.
| Market | Horizon | Best bid | Best ask | Midpoint |
|---|---|---|---|---|
ANTH-IPO-DATE | By Dec 31 | Nov 20, 2026 | Nov 21, 2026 | Nov 20, 2026 |
How it settles
- The number is the first day (US Eastern date) Anthropic’s shares trade on a public exchange. Its S-1 was filed Oct 26, 2026; reports say Nasdaq, ticker ANT. An acquisition by a company that is already public isn’t a listing.
- Strikes sit on the midnights (UTC) between days, so it never pushes. At a strike of Nov 20, Higher wins if trading starts on Nov 20 or later (or not by the deadline), and Lower wins if trading starts by Nov 19.
- Each contract expires 2 days after its strike’s midnight. If Rizon has resolved the market by then (from the exchange’s listing and SEC filings), it settles on the reported day; if not, Higher wins.
- Rizon resolves it by hand. Until it does, the book keeps trading, including strikes the event has already decided, so a resting order can fill after the news.
- If it hasn’t happened by Dec 31, 2026, the number is Dec 31, 2026 and Higher wins at every strike. Strikes run from tomorrow to Dec 31, 2026, and each one trades until its midnight passes (resting orders at it are then canceled and refunded); trading closes at 00:00 UTC on Dec 31, 2026.
- In the API the number and the strikes are Julian Day Numbers: 2,461,360 is Nov 15, 2026, and the strike 2,461,359.5 is the midnight that starts it.
- A win pays 2× your size; a loss pays nothing.
Source: The exchange’s listing and SEC filings, resolved by Rizon.