Bitcoin Stock-to-Flow Model Explained: Does It Still Work in 2025?
#bitcoin-stock-to-flow-model-explained
Introduction
Few Bitcoin concepts have sparked as much debate as the Stock-to-Flow model. When it emerged in 2019, it seemed revolutionary — a mathematical framework that explained Bitcoin's price history with startling accuracy and projected six-figure valuations ahead. Traders studied its charts religiously. Analysts quoted it in research. Critics dismissed it as wishful thinking.
Here we are in 2025, and the debate rages on.
Let's dig into what the Stock-to-Flow model really is — its origins, mathematical foundation, successes, failures, and whether it belongs in your analysis toolkit. We'll separate the hype from reality and give you an honest look at Bitcoin's most controversial valuation framework.
What Is the Stock-to-Flow Model?
Stock-to-Flow measures scarcity by comparing existing supply (the "stock") to new annual production (the "flow").
The calculation is simple:
S2F Ratio = Stock / Flow
A high ratio means it would take many years of current production to double existing supply — indicating scarcity. Gold has an S2F ratio around 60, meaning above-ground supply is 60 times larger than annual mining output. Silver sits near 22. Oil, consumed quickly, hovers around 1.
The basic idea: when something becomes harder to produce relative to what already exists, it gets scarcer and more valuable.
Bitcoin's Unique Position
Bitcoin caps at 21 million coins. New supply comes through mining, with issuance halving every four years. This predictable reduction means Bitcoin's flow shrinks while its S2F ratio jumps with each halving.
Before 2012's halving, Bitcoin's S2F ratio sat around 11. After 2016, it climbed to about 25. The 2020 halving pushed it to approximately 56 — matching gold's territory. April 2024's halving drove the ratio past 100, theoretically making Bitcoin scarcer than any commodity in history.
The model's core thesis: rising scarcity drives rising prices.
The Origins: PlanB's 2019 Analysis
An anonymous Dutch analyst called PlanB popularized Bitcoin's Stock-to-Flow model through a March 2019 Medium article titled "Modeling Bitcoin's Value with Scarcity."
PlanB ran regression analysis on Bitcoin's price history against its S2F ratio, finding a remarkably strong relationship. The original model's R-squared exceeded 0.94, meaning the S2F ratio explained over 94% of Bitcoin's price variance. For a single-variable model tracking such a volatile asset, this looked impressive.
The model predicted that after 2020's halving, Bitcoin's S2F ratio would match gold's, with prices reaching roughly $100,000 by cycle's end.
Bitcoin peaked at $69,000 in November 2021. Getting close, but missing the target. What happened next makes the story more complicated.
The S2FX Extension
In 2020, PlanB expanded into the Stock-to-Flow Cross-Asset model (S2FX), incorporating silver, gold, and different Bitcoin "phases" to argue that Bitcoin makes discrete valuation jumps as adoption phases shift.
S2FX projected Bitcoin hitting $288,000 during 2020–2024. That didn't happen, and serious analysts have largely abandoned this version.
Why the Model Caught Fire
Understanding the model's appeal reveals both Bitcoin's nature and the framework's limitations.
It reflected Bitcoin's actual design. The halving schedule isn't speculation — it's protocol-embedded. Scarcity isn't theoretical; it's structural. This gave the model credible foundations that pure technical analysis lacks.
Historical data fit remarkably well. When PlanB published in 2019, the model tracked Bitcoin's price across three halvings with stunning accuracy. Such backtesting performance is rare and compelling.
It provided conviction during volatility. Markets test psychology relentlessly. A model saying "Bitcoin should reach X by date Y" — however imperfect — helps investors weather storms. The model became a psychological anchor as much as an analytical tool.
People could wrap their heads around the story. Scarcity creates value. Gold is scarce and valuable. Bitcoin becomes scarcer than gold. Therefore Bitcoin becomes valuable. Simple enough for anyone to understand.
The Mathematical Foundation
Here's what's actually happening under the hood.
PlanB performed log-linear regression between Bitcoin's S2F ratio and market capitalization, finding:
ln(Market Cap) = a × ln(S2F) + b
Or in standard form:
Market Cap = e^b × S2F^a
Historical data determined coefficients a and b. The model predicts that each S2F doubling increases market cap by a consistent multiplier — a power-law relationship, not linear growth.
This matters because each halving roughly doubles the S2F ratio, suggesting predictable market cap jumps. Halvings become embedded catalysts in the model's structure.
What the Model Got Right
Before criticism, credit where it's due — the model nailed several important points.
Directional accuracy through 2021. Bitcoin's price largely followed the model's path through 2012, 2016, and 2020 halving cycles. Each halving preceded major bull runs. The model predicted this pattern and it materialized.
Supply dynamics matter. Regardless of price accuracy, the model correctly emphasized Bitcoin's supply schedule as a fundamental economic driver. The 2024 halving cut daily issuance from 900 to 450 BTC — a supply shock markets historically need time to absorb.
Commodity framing worked. Comparing Bitcoin's scarcity to gold and silver helped institutional investors understand the asset class. This positioning supported the institutional adoption wave of 2020–2021.
Where the Model Failed
Honest analysis requires confronting the breakdowns.
The 2021–2022 Reality Check
Bitcoin peaked around $69,000 in November 2021. The original S2F model suggested $100,000–$288,000 by year-end 2021. This wasn't a minor miss — it was a significant failure to reach confidently projected levels.
After peaking, Bitcoin crashed to roughly $16,000 by late 2022, a level the model considered deeply undervalued. If mechanically accurate, prices should have rebounded quickly. They didn't for over a year.
The Demand Blind Spot
Here's the fundamental flaw: Stock-to-Flow only models supply. Demand doesn't exist in the equation.
Extreme scarcity means nothing without demand. Bitcoin's price reflects supply and demand intersection, but S2F ignores demand entirely.
In 2022, demand collapsed from multiple factors — rising rates, Terra/LUNA's implosion, FTX's collapse, broad risk-off sentiment. The model had no mechanism for any of this. It assumed demand would grow proportionally with scarcity — an assumption, not a law.
Statistical Problems
Quantitative analysts raised legitimate methodological concerns:
- Spurious correlation: Two upward-trending variables often appear related without causal connection. Bitcoin's price and S2F both climb over time, which can create misleading correlations.
- Overfitting: Strong historical performance can fail future predictions when models fit too closely to past noise rather than underlying patterns.
- Non-stationarity: The time series don't meet standard regression assumptions, which undermines the statistical validity of PlanB's confidence intervals.
These aren't fringe criticisms — credentialed statisticians and economists raised them, and they remain unresolved.
Stock-to-Flow in 2025: Current Status
The honest verdict: as precise price prediction, Stock-to-Flow has failed. As a conceptual framework for supply dynamics, it retains value.
The 2024 Halving Cycle
April 2024's halving cut block rewards from 6.25 to 3.125 BTC. Bitcoin's S2F ratio now exceeds 100, reaching unprecedented theoretical scarcity. Model projections for this cycle range from $200,000 to $500,000, depending on interpretation.
Bitcoin did hit new highs in 2024, crossing $100,000 for the first time. This aligns with the model's directional logic — halving precedes bull run — but specific price levels and timing haven't materialized as projected.
Whether that changes through 2025–2026 remains unknown. What's clear is that treating the model as precise price oracle has repeatedly misled investors.
What Analysts Actually Use
Serious Bitcoin analysts have shifted toward multi-indicator frameworks rather than single-model dependence. S2F ratio becomes one input among many, not a standalone predictor.
Other on-chain metrics prove more dynamic and responsive to real market conditions:
- MVRV Z-Score: Compares market value to realized value, identifying overheated or undervalued conditions relative to actual cost basis.
- NUPL (Net Unrealized Profit/Loss): Measures aggregate unrealized profit/loss across all holders, revealing market sentiment and cycle position.
- Hash Rate and Mining Difficulty: Reflect miner confidence and network security as leading indicators of long-term health.
- Miner Revenue: Shows whether miners face financial stress, signaling potential sell pressure or capitulation.
These don't predict single price targets. Instead, they provide real-time cycle positioning — whether conditions are euphoric, depressed, or transitional.
Platforms like Horizon Forecast track all these metrics together, with interactive charts, historical data back to Bitcoin's 2009 genesis, and five-second updates. When assessing Bitcoin's structural strength or vulnerability, this multi-dimensional view proves far more actionable than any single model's curve.
Integrating S2F Into Your Framework
Rather than treating Stock-to-Flow as a price oracle, here's how to use it effectively:
1. Cycle context, not price targets.
Halving-driven supply reduction is real and historically significant. S2F provides structural perspective on Bitcoin's supply cycle position — valuable context even with unreliable price predictions.
2. Combine with demand indicators.
S2F covers supply. MVRV, NUPL, and exchange flows reveal demand and holder behavior. Together, they create a complete picture.
3. Consider it a floor reference, not ceiling.
Some analysts use S2F as rough lower-bound guidance — Bitcoin trading well below the model's curve might suggest undervaluation relative to supply dynamics. But the model lacks ceiling mechanisms, and projections above $200,000 deserve skepticism.
4. Focus on halvings, not formulas.
The most durable S2F insight isn't the regression equation — it's that halvings matter. Each has preceded significant bull markets. Understanding why (reduced miner sell pressure, renewed narrative attention, supply shock psychology) beats plugging numbers into equations.
Conclusion
The Bitcoin Stock-to-Flow model is neither the crystal ball early supporters claimed nor the pseudoscience harsh critics suggest. It's a framework built on Bitcoin's real scarcity properties that captured something true about the asset's economics while overreaching on precision.
In 2025, the model's directional logic retains some merit. Halvings still reduce supply. Bitcoin still reaches new highs in subsequent cycles. However, specific price targets have consistently missed their marks, and structural criticisms — especially the missing demand variable — remain valid concerns.
The most successful Bitcoin analysts don't rely on single models. They track multiple indicators simultaneously, understand what each measures, and build comprehensive views of actual market conditions.
To track the metrics that matter — from MVRV Z-Score and NUPL to hash rate, mining difficulty, and miner revenue — with real-time data and complete historical context, explore what Horizon Forecast offers.
The model provides a starting point. Real analysis begins with the data.