Stock-to-Flow (S2F)
A scarcity model valuing an asset by existing supply divided by annual new production — famous, and famously contested.
Stock-to-flow measures scarcity as existing supply (“stock”) divided by yearly new issuance (“flow”). Gold has a high ratio; Bitcoin’s rises with each halving as issuance drops. A widely-circulated 2019 model used S2F to project Bitcoin’s price, and it gained a large following during the 2020–21 bull run.
It’s included here because it’s culturally unavoidable — and because understanding its criticism is part of crypto literacy. The model’s price predictions broke down badly afterward, and statisticians noted deep methodological flaws (spurious correlation, no demand side). S2F illustrates a real property (programmed scarcity) but is not a reliable price oracle. Treat it as a scarcity concept, not a forecast.