Art Market Performance Index – Methodology
AMPI White paper →
What we measure
The AMR Art Market Performance Index tracks auction market sentiment by aggregating Artist Prices (APs)—a per-artist measure derived from hammer prices—across a broad cohort each month.
How AP is calculated
Sales for each artist are evaluated over a 24-month rolling window. AMR tested several schemes and adopted a date-sensitive weighted average, giving proportionally more weight to recent sales while treating sales within the same month equally. Exponential smoothing is then applied to reduce high-frequency noise.
How the index is formed
APs are ordered and all (or the first 10,000) are eligible for inclusion. The index level at time t is 1000 × (sum of APs at t / sum in the base period). This is repeated monthly, with the full history smoothed. Constituent turnover is modest; testing shows high month-to-month retention of artists.
Scope & quality controls
Data come from major auction houses worldwide (full list and 2022 weights in the paper). Hammer prices are used net of buyer’s premium and converted to GBP at the Bank of England rate on the sale day. A Core index excludes artists with fewer than 30 sales in two years, while the broad index retains “rare” artists to capture high-value, thinly traded names.