Index price vs mark price: what's the difference?

An index price is a reference for the underlying asset or basket. A mark price represents a market-specific pricing measure used for defined calculations. An execution price is the amount at which a trade actually fills. These numbers can differ because they answer different questions.

The exact roles depend on the venue. This guide defines the prices first, then shows how N1 uses them.

What an index price represents

An index uses a specified source or calculation method to create a reference. For an asset with multiple spot markets, the method may combine external observations. For a basket such as TCGX, it combines selected card-variant observations under documented rules.

That reference is not automatically an offer available to buy or sell. In TCGX, the inputs can be provider-reported prices rather than completed sales or executable quotes. The basket's publication time and the timestamps of its inputs are also different things.

Read what is a trading card index? for that example. Regardless of the underlying market, the source and freshness of the reference matter when interpreting it.

What a mark price represents

N1's documentation describes mark price as reflecting market pricing relative to the index. In central limit order book markets, it is derived from available bids and asks. For RFQ markets, eligible market-maker pricing is used to measure the funding premium.

A mark can therefore differ from the external reference. Its displayed value also does not reserve a fill at that level for a particular side and size. To enter or close a position, you still need an executable order or quote.

Which price does N1 use?

N1 documents the following roles. Both index and mark contribute to its funding calculation, in different ways:

A simple example

Assume an illustrative linear market shows an index of $100, a mark of $102, a best bid of $101.50, and a best ask of $102.50. A trader previously bought one unit at $101.

Using the mark alone, displayed unrealized trading PnL in this simplified example is $1: $102 minus $101. If the trader sells into an available $101.50 bid, the execution-price difference is $0.50 before fees and funding. The two results differ because the valuation measure and fill price differ.

If a conditional order is configured to activate when index price reaches $103, a mark at $103 would not by itself satisfy that index-based condition. Activation is also separate from execution: an activated order must still meet the applicable order and liquidity conditions.

The example omits contract multipliers, funding, fees, collateral changes, and account-level margin effects. It demonstrates price roles rather than a complete account calculation.

Funding, liquidation, and execution are separate

Funding relates market pricing to its reference under the venue's formula. It does not force every trade to fill at index or mark. Read funding rates explained for that mechanism.

Similarly, the price used in a risk calculation is not necessarily the price achieved during liquidation or an ordinary exit. Execution conditions and account rules still matter. How liquidation works and the all-in cost of a trade explain those additional parts.

If reliable index data are unavailable, N1's documentation says trading may be restricted until valid pricing resumes. A displayed reference is not a guarantee of continuous access or an exit.

Common questions

Is mark price my guaranteed closing price?

No. Your close depends on executable liquidity, size, side, and order conditions. Mark price is a calculation measure.

Sources

• N1: oracle, index, and mark prices
• N1: take profit and stop loss
• N1: TCGX methodology