Cross-Asset Tail Risk API

Ranks the major markets by how brutal their bad days are, computed live from Yahoo Finance daily closes — no key, nothing stored. Volatility and the Sharpe ratio assume returns are symmetric and well-behaved, but the losses that actually blow up a book live in the left tail — the rare, deep down-days a standard-deviation number smooths away. This API measures that tail directly. For each market it returns Value-at-Risk (the daily loss not exceeded on 95% / 99% of days, both the historical percentile and the normal-distribution parametric estimate), the Conditional VaR / Expected Shortfall (the average loss on the worst days, beyond VaR — how bad the bad days really are), and the shape of the return distribution: skewness (negative = crash-prone, a long left tail) and excess kurtosis (high = fat-tailed, outlier-prone). The asset endpoint returns one instrument's full tail-risk profile; the screener endpoint ranks the cross-asset universe (equities, sectors, commodities, bonds, FX and crypto; filterable by class) from the most tail-risky to the safest. This is the cross-asset distribution-tail / VaR-CVaR cut — distinct from the bring-your-own-series risk-metrics engine, the crypto-only coin risk scorecard, the drawdown-pain (Ulcer) screener and the volatility APIs. It is the left tail, measured across the whole book.