A public price needs a public recipe.
The Spot Index is the volume-weighted median fill price across eligible instruments over a rolling five-minute window, expressed in dollars per million tokens and rebased to the general-chat family.
Eligibility
A fill counts if it prints on a listed instrument, is at least 10k tokens, and is not cancelled, busted, or an out-of-band correction.
Window
Every second we take the last five minutes of eligible fills. Size is token volume. The statistic is the volume-weighted median, not the mean.
Rebase
Each family is scaled to general chat (MID-128K) using the trailing-week relative mid, so a frontier print does not dominate the number.
Publication
The live index ticks every second. A daily settlement value prints at 17:00 ET and is the mark for financially-settled contracts.
Weights
Constituent weights are trailing-week notional, floored at 2% and capped at 45% so no single family owns the print. Weights republish each Monday 00:00 ET. They are not adjusted by committee, and they are not a quality score.
Corrections
A busted fill is removed from the window as soon as the trade is reversed. We do not restated printed seconds. The daily 17:00 ET value can be revised until 18:00 ET the same day if a bust lands in that hour; after that it is final.
What stays out
Test keys, internal crosses, fills marked indicative, and any venue in the process of being delisted. If a family has fewer than three live venues it is held in the index at its last weight but its new fills do not update the level until a third venue is back.
Using the print
Buyers treat the live index as a budget input for max_price. Funds mark financially-settled products to the daily print. Neither use is an offer to trade the index itself. The board and the tape are the source; this page is the recipe.