What is Stock-to-Flow?
Stock-to-Flow (S2F) is a valuation model originally developed for commodities like gold and silver. It was applied to Bitcoin by the pseudonymous analyst PlanB in 2019 and became one of the most widely discussed Bitcoin valuation frameworks.
The model is based on a simple concept: the value of a scarce asset is determined by the ratio of its existing supply (stock) to the rate of new production (flow).
Stock-to-Flow ratio = Existing supply / Annual new production
A high S2F ratio means the asset is scarce relative to new production -- like gold, which has an S2F ratio of approximately 60, meaning it would take 60 years of current gold mining to double the existing supply.
A low S2F ratio means the asset is abundant relative to new production -- like oil or agricultural commodities, where supply can be rapidly expanded to meet demand.
Bitcoin's Stock-to-Flow dynamics
Bitcoin has a mathematically predetermined supply schedule hardcoded into its protocol. 21 million Bitcoin will ever exist. The rate of new Bitcoin creation is cut in half approximately every four years in an event called the Halving.
This creates a predictable, increasing Stock-to-Flow ratio over time:
Before the 2012 Halving: S2F approximately 11
After the 2012 Halving: S2F approximately 25
After the 2016 Halving: S2F approximately 50
After the 2020 Halving: S2F approximately 56
After the 2024 Halving: S2F approximately 120
For context, gold's S2F is approximately 60. After the 2024 Halving, Bitcoin's S2F exceeded gold's for the first time -- making Bitcoin theoretically more scarce than gold by this measure.
PlanB's original model argued that this increasing scarcity, following the same mathematical pattern as gold and silver, would drive Bitcoin's price higher in a predictable trajectory following each Halving.
What the model predicted
PlanB's Stock-to-Flow model and its cross-asset extension (S2FX) made specific price predictions that were widely discussed:
The original S2F model predicted Bitcoin would reach approximately $100,000 following the 2020 Halving -- Bitcoin reached $69,000 in November 2021, falling short of the prediction but in the same order of magnitude.
The S2FX model predicted prices of $288,000 per Bitcoin in the 2020-2024 cycle. Bitcoin did not reach this target in the 2021 bull market.
For the post-2024 Halving cycle, various S2F-based models suggest price targets ranging from $100,000 to $500,000+ depending on the methodology and assumptions used.
What the model gets right
The Stock-to-Flow model correctly identifies several important characteristics of Bitcoin:
Scarcity is real and increasing. Bitcoin's supply schedule is immutable. The Halving events do reduce new supply. The mathematical scarcity argument is factually correct.
Post-Halving appreciation is historically consistent. In every cycle following a Halving event, Bitcoin has reached new all-time highs within 12-18 months. The 2024 Halving is following this pattern -- Bitcoin reached $108,000 in December 2024 before the current correction.
Long-term trend. Despite missing specific price targets, the general direction predicted by S2F -- Bitcoin's long-term price trend moving higher with each cycle -- has been directionally correct.
What the model gets wrong
The Stock-to-Flow model has been subject to significant academic criticism:
Demand is ignored. S2F measures supply characteristics only. An asset can be infinitely scarce and still be worth zero if nobody wants it. The model assumes demand will always meet or exceed the implications of scarcity -- an assumption that may not hold in all scenarios.
Precise predictions fail. The model's specific price predictions have missed their targets significantly. Bitcoin did not reach $100,000 in the 2020-2021 cycle on the predicted timeline, and the 2021 peak fell well short of S2FX predictions.
Unfalsifiability criticism. Critics argue that the model is adjusted retroactively to fit historical data rather than making genuine predictive predictions. When prices deviate from the model, proponents adjust parameters rather than rejecting the model.
Statistical methodology concerns. Several academic papers have argued that the apparent statistical relationship between S2F and Bitcoin's price is spurious -- driven by the shared upward trend in both variables rather than genuine causal relationship.
S2F in the 2026 context
Following the April 2024 Halving, Bitcoin's Stock-to-Flow ratio reached approximately 120 -- the highest in its history and more than double gold's ratio.
The post-Halving pattern has historically played out 12-18 months after the event. Bitcoin did reach $108,000 in December 2024 -- approximately 8 months post-Halving. The subsequent correction to $73,000-$74,000 and recovery to $77,000+ in April 2026 is consistent with mid-cycle consolidation patterns seen in previous cycles.
S2F-based analysts who account for this mid-cycle correction pattern suggest the second leg of the post-Halving bull market may be beginning in April-May 2026 -- with targets ranging from $150,000 to $250,000 within 12 months.
These are analyst projections, not AIOKA predictions. AIOKA does not make price forecasts -- the council assesses current conditions and near-term probability-weighted direction.
How AIOKA uses Stock-to-Flow
AIOKA's Chain Oracle agent monitors the Stock-to-Flow ratio as part of its cycle positioning assessment. S2F is used as a long-term valuation context signal rather than a precise entry/exit trigger.
The current S2F reading of approximately 120 -- combined with the post-Halving cycle timing, on-chain accumulation metrics, and institutional flow data -- contributes to the council's current market regime assessment.
The bottom line
The Bitcoin Stock-to-Flow model is a useful framework for understanding Bitcoin's supply-side scarcity dynamics and long-term cycle positioning. Its specific price predictions have been imprecise. Its directional thesis -- that increasing scarcity drives long-term appreciation -- has been broadly correct.
Use S2F as one input among many -- a long-term valuation lens that provides context for shorter-term signals. It is most useful for understanding where you are in the multi-year cycle, not for timing individual trades.
At an S2F ratio of 120 following the 2024 Halving, Bitcoin is in historically unprecedented scarcity territory. Whether that scarcity translates to $150,000 or $500,000 depends on demand -- which no supply-side model can predict.
AIOKA monitors Stock-to-Flow as part of its 27-signal framework. Current cycle assessment visible at aioka.io/live.