Ulcer Index API
Ranks a cross-asset universe by how painful each market's drawdowns have been, and how much return it paid for that pain, computed live from Yahoo Finance daily closes — no key, nothing stored. Volatility treats an up-move and a down-move as equally risky, but investors only lose sleep over the downside: the depth of the fall from the last high and how long it drags on before recovering. The Ulcer Index (Peter Martin) captures exactly that — the root-mean-square of every day's percentage drawdown from the running peak, so a deep, long drawdown is penalised far more than a brief dip and a market that keeps making new highs scores near zero. From it comes the Martin ratio (the Ulcer Performance Index) — annualised excess return divided by the Ulcer Index — the return earned per unit of drawdown pain, a downside-only cousin of the Sharpe ratio. The asset endpoint returns one instrument's full pain profile: Ulcer Index, maximum, average and current drawdown, longest time underwater, the Martin ratio and the pain ratio. The screener endpoint ranks the 21-instrument universe (equities, sectors, commodities, bonds, crypto; filterable by class) by Martin ratio (best pain-adjusted return) or by Ulcer Index (smoothest ride). This is the drawdown-pain / Ulcer-Index cut — distinct from a current-drawdown monitor (a point-in-time snapshot of how far below peak each market is), the Sharpe/Sortino/Calmar screener (Calmar uses only the single worst drawdown) and the price APIs. It scores the whole shape of the pain, not one point of it.
api.oanor.com/ulcerindex-api
