Index price, mark price, last price

You open the PKMN market at /trade/PKMN and see a number on the screen. Then a second number, slightly above or below the first. Anyone who has traded a perpetual knows what to ask next: which one is real, and how far apart can they drift? On a perpetual over a liquid asset, arbitrage against the spot market does most of the work of keeping them together. On a Quanta market the gap has a hard ceiling, and the matching engine enforces it.

Three prices, three jobs

Every market on a Quanta index shows three prices, and each one has a single job.

Price	What it is	What it is used for
Index price	Quanta's published level for the category	The reference the market tracks
Last price	The price of the latest trade on the orderbook	Seeing what just happened
Mark price	The index and the book combined, clamped to a band around the index	Valuing positions, liquidation

Index price

The index price is the level Quanta's index engine computes from real sales of graded cards, with the public on-chain record of vaulted card sales as the verifiable layer it reads (What is a Quanta index). Quanta's oracle delivers it to the market at least once per second. No order, no position and no volume of buying or selling on the book can shift it by a cent, because the index is made of card sales, not perpetual trades. Where those sales come from is covered on The data source, and how they turn into a single level is on Methodology principles.

Last price

The last price is where the most recent trade on the orderbook matched. It is the most immediate number on the screen and the least important one. A single small order at an odd price sets a last price, but it does not set the market. Nothing about your position is calculated from it. If it jumps around, your margin, your liquidation level and your funding stay where they are.

Mark price

The mark price is the one your position actually lives on. Unrealized PnL is measured against it, and liquidation triggers on it, never on the last price (Margin, leverage and liquidation). Funding is priced on the market's distance from the index, as defined in the market parameters, rather than on the mark (Funding). The matching engine builds the mark from two inputs, the index price and the state of the orderbook, and then applies the rule this page is about: the result is clamped to a band around the index. If the book would push the mark above the top of the band, the mark sits at the top of the band. If the book would push it below the bottom, the mark sits at the bottom. The band is a few percent wide at most, and the exact factor is shown on the market page.

The band

Picture it on a chart. The index moves the way an index does: slowly, driven by real sales. Trades on the book scatter around it, and during a burst of buying or a thin moment a few of them print outside the band. The mark follows the book while the book stays near the index, and stops at the edge once the book runs off. Funding then does the rest, charging the crowded side until it comes back (Funding).

The mark price is anchored to the index inside a narrow band, so what you trade is the index.

The engine enforces this in code on every price update. Nobody has to step in, and it does not rely on the market choosing to respect a target. A trader who wants to drive the book far above the index can place the orders and may even get them filled. Your fill is always the book's price. Buy above the band and the position is marked back inside it the moment it opens, with the difference showing as unrealized PnL from the first second. What no trader can do is push the mark price past the band. The most the book alone can do to any position, in value or in distance to liquidation, is the width of the band, and leverage scales that width the same way it scales any other move (Margin, leverage and liquidation).

No spot market needed

On a perpetual over a liquid asset such as a major cryptocurrency, arbitrage is what mostly keeps the market near its reference price. If the perpetual trades rich, someone sells it and buys the asset on a spot exchange until the gap closes. The asset itself is the anchor. A category of graded cards has no such venue. You cannot buy graded Pokémon in one trade; you can buy a single card from a single seller and wait for it to sell again. Nobody can arbitrage the index with physical cards, so the physical market is not what holds the perpetual in place.

The band does that job instead. Because the mark price is clamped, the maximum distance between what you trade and the category's price is fixed and shown on the market page. Funding covers the rest of the way. A Quanta market does not need a spot market in the index to behave like one: the index is the anchor and the engine holds the line. Perpetuals, explained for collectors describes how this looks from inside a position.

A feed built to fail safe

A band around the index is only as good as the index price reaching the engine, so the oracle is designed to fail safe rather than fail silently.

The index price arrives from redundant publishers, not a single process. The guardrails take the median across sources, so one publisher sending a wrong value cannot move the price the engine sees. The engine also watches for silence. If fresh data stops arriving, the market does not keep trading against the last number it received. A stale feed pauses new risk: the market switches to reduce-only, every position can still close, and new positions open again as soon as the feed is fresh. Feed freshness is one of three health conditions monitored around the clock, and Market safeguards covers all three along with what reduce-only means in practice.

With redundancy, the median and silence detection working together, the band is drawn around the current Quanta index, and when the index is not fresh the market takes on no new risk. The number is never a guess.