Stock-to-Flow

Ratio of existing supply (stock) to new annual supply (flow). PlanB's S2F model attempted to formalise Bitcoin's halving-cycle price relationship by predicting price as a function of S2F. Had striking fit through 2020-2021 (BTC at $69K) but substantially missed predictions in 2022-2023 (predicted $100K+ when prices were $15-30K). Now controversial — some argue it captured a real relationship, others retrofitted curve-fitting. Use with extreme caution.