The STH Risk Index is a short-cycle investor behavior risk indicator (0-100) combining three Short-Term Holder (STH, coins younger than 155 days) metrics, each normalized by cumulative historical percentile rank (no look-ahead bias): SOPR STH (Spent Output Profit Ratio of coins moved by short-term holders), Loss Ratio STH (realized loss / total realized volume, near 0 means complacency, near -1 means capitulation), and MVRV STH (Market Value / Realized Value of short-term holder coins).

Because it only looks at short-term holders, it reacts faster to price swings than long-cycle indicators like the Macro Risk Index, making it useful for spotting local overheating or capitulation within an ongoing trend.

The line color follows the score itself, matching the five documented risk zones: Accumulation (0-20), Low Risk (20-40), Moderate (40-60), Elevated (60-80) and High Risk (80-100).

It is one of the three equal-weight components of the On-Chain Risk Index, alongside the Macro Risk Index and the Options Skew Risk Score.