The Stock to Flow (S/F) Ratio is a popular model that assumes that scarcity drives value. Stock to Flow is defined as the ratio of the current stock of a commodity (i.e. circulating Bitcoin supply) and the flow of new production (i.e. newly mined bitcoins). Bitcoin's price has historically followed the S/F Ratio and therefore it is a model that can be used to predict future Bitcoin valuations. This metric was first coined by PlanB. For a detailed description see this article.

This is the Point-in-Time (PiT) variant of Stock-to-Flow Ratio. PiT metrics are strictly append-only and their history is immutable. The historic data does not necessarily reflect the best current knowledge, but the information at the time when a data point was first computed. PiT metrics are ideal candidates for applications in model backtesting and related quantitative purposes. Read our article on PiT metrics for more information.