What Are Index Price, Mark Price, and Last Traded Price?

Index price, mark price, and last traded price are fundamental and extremely important concepts when trading crypto derivatives on exchanges. Let's find out what they are and their role in making investment decisions.

When you trade on spot markets, you essentially exchange a certain amount of an asset for a different amount of another asset. However, when you trade derivatives like futures, you do not necessarily own an asset, but rather trade contracts that reference the asset. This leads to the demand of derivatives contracts for spot price data, so that activities such as longing and shorting futures contracts are viable. That's where index price, mark price, and last traded price come into play.

The exchange index price, or often called index price in short, is the average spot price of a certain token on major exchanges. Usually, the index price of one cryptocurrency is calculated differently from one exchange to another, depending on which exchanges constitute the list of "major exchanges" whose data are taken into consideration.

The index price is calculated as follows:

Index price = Spot price of exchange 1 x Weight of exchange 1 + Spot price of exchange 2 x Weight of exchange 2 + …

The higher the trading volume of an exchange, the higher the weight number of that exchange. This means that the exchange with greater trading volume will have more influence over the index price.

The purpose of index price is to provide a fair and accurate price of an asset in all facets of derivatives trading, including futures, perpetuals, and funding rates to name a few. In other words, index price makes sure that derivatives contracts are settled at the right price.

As one of the biggest derivatives exchanges in the crypto market, Bitget commits to offering the best products and the fairest and most accurate prices possible for users. Index prices on Bitget are derived from three top CEXes, which are Binance, OKX, and Huobi. You can see the sources used to compile index price at the lower half in every derivatives trading page on Bitget like this:

Mark price is another important factor of derivatives trading. It is used as a reference in triggering liquidations, as well as in calculating leverage and unrealized profit and loss. Its purpose is to make performing liquidations fair and manipulation-resistant.

Two things to note:

Basically, the mark price is the mid-price of the order book, but to make sure the mark price is fair and does not diverge too far from the spot price, it is bound by the index price, which means that mark price is influenced by the spot price from various major exchanges. However, the actual formula to calculate mark price differs from one type of derivatives to another, and it is too complicated to get into such nitty-gritty in this 101 article, so we will only look into the basics of mark price.

Apart from the index price, mark price also takes another component called the moving average basis into account. This component serves one goal, which is to offer a constantly updated average price of a certain token over a period of time, thereby providing a fair price and limiting unnecessary liquidations when the volatility is high.

Important things need to be repeated: The mark price is the price that you need to pay attention to for leverage, profits-and-loss calculations, and liquidations.

Last traded price is the latest price at which derivatives contracts are traded and it is updated in real-time. While mark price is only used to calculate unrealized profit and loss, the last traded price is actually used to determine the realized profit and loss.

Because of their nature and how they are calculated, the last traded price may differ from the mark price.

As the leading crypto derivatives exchange, Bitget has already released a spectrum of products vital to the sustainable development of the digital space. Our curated financial instruments include Bitget Coin-Ⓜ Futures, Bitget USDT-Ⓜ Futures, Bitget USDC-Ⓜ Futures, Bitget Copy Trade, Bitget Spot Trading, together with powerful tools ( Bitget Futures Grid, Bitget Spot Grid) and a variety of DeFi-inspired services.

Disclaimer: The opinions expressed in this article are for informational purposes only. This article does not constitute an endorsement of any of the products and services discussed or investment, financial, or trading advice. Qualified professionals should be consulted prior to making financial decisions.