How the Shotgun index works
An index is 1,000 times the median, across its items, of each item's current price divided by that item's base price. The base price is the median of the item's first week of hourly prices from April 23, 2026 (or from when the item first appeared), so new items join at parity instead of being left out. Using the median means one mispriced or illiquid listing cannot move the index.
An index publishes a value for an hour only when at least 5 of its items have a price that hour; otherwise the hour is skipped rather than estimated from a thin sample. Values recompute hourly.
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Frequently asked questions
What does a price index value of 1,000 mean?+
Every CS2Cap price index reads 1,000 at its epoch, April 23, 2026. A value of 1,200 means the typical item in that index costs 20% more than it did then; it is a measure of relative movement, not a dollar amount.
How is a price index calculated?+
Take every item in the index, divide its current price by its base price (the median of its first week of prices), and take the median of those ratios. Multiply by 1,000. Because it is a median of price ratios, a single overpriced listing or a thinly traded item cannot swing the whole index, and there is no compounding: a bad price in one hour affects that hour only.
Why does an index sometimes show a gap or go flat?+
An index requires at least 5 priced items to publish a value for an hour. When fewer items have a price, that hour is skipped rather than computed from a thin, unrepresentative sample.
How often do index values update?+
Index values recompute hourly from the same pricing pipeline that feeds the rest of CS2Cap. The page shows the hour the data is current to.
How is this different from CS2 Market Cap?+
Market Cap totals the USD value of the tracked catalog. Price indexes strip the dollar amount out and track relative movement instead, so a category, weapon, rarity, or variant can be compared on how its typical item moved, independent of its total size.
