Skip to main content
The Everstrike Mark Price is a manipulation-resistant reference price that Everstrike uses to evaluate margin sufficiency and trigger liquidations. Using the Last Traded Price for these purposes would expose traders to deliberate price manipulation — a single large trade could push the price far enough to trigger cascading liquidations. The Mark Price reduces that risk by grounding itself in both external market data and a smoothed view of the order book.

​
Calculation Overview

Everstrike calculates the Mark Price in four sequential stages:
  1. Index Price — derive a reference price from real-time data across selected spot exchanges.
  2. Fair Price — compute bid and ask impact prices from the order book depth.
  3. EMA smoothing — apply an exponential moving average to the difference between the Fair Price and Index Price.
  4. Clamping — constrain the final Mark Price to a permitted range around the Index Price.

​
Index Price

The Index Price is the average market price of an asset, calculated from real-time data across a set of selected spot exchanges after excluding statistical outliers. It represents the broader market consensus price and updates once per second. See Index Price for the full list of constituent exchanges and how option index prices are derived.

​
Fair Price

The Fair Price is derived from two sources: the Impact Price (the average fill price at a given order book depth X) and the Scaled Best Price (a multiplier applied to the current best bid or ask). For bids:
For asks:
Everstrike then averages the two to produce a single Fair Price:
The impact depth X varies by trading pair. For the Bitcoin perpetual futures contract, X is currently 0.3 BTC. You can retrieve the value for each pair from the Markets API.

​
Scaled Best Price

The Scaled Best Price applies a pair-specific multiplier to the current best bid or ask:
The multiplier is pair-specific. For the Bitcoin perpetual futures contract it is currently 0.001. The Markets API provides the current multiplier for each trading pair.

​
Mark Price Calculation

First, Everstrike calculates the Fair Price basis — the gap between the Fair Price and the Index Price:
It then adds an exponentially smoothed version of that basis to the Index Price:
EMA_Y is an exponential moving average calculated over Y one-second periods. For the Bitcoin perpetual futures contract, Y is currently 30. Finally, Everstrike clamps the result within a pair-specific permitted range around the Index Price:
This keeps the Mark Price between (1 − Z) × Index Price and (1 + Z) × Index Price.
Z is pair-specific. For perpetual futures, Z is a fixed percentage. For perpetual options, Z is dynamic — Everstrike derives it from the option’s Black-Scholes theoretical value and the price of its underlying asset. You can retrieve the current value for each pair from the Markets API.