When a pseudonymous Dutch institutional investor known only as "Plan B" dropped the Stock-to-Flow (S2F) model on the crypto world, it ignited one of the most heated debates in Bitcoin history. The model claimed to predict Bitcoin's future price with uncanny precision, treating the digital asset more like digital gold than a typical tech stock. Now, years later, the question on every investor's mind remains the same: does Plan B's Bitcoin thesis still hold water, or has the prophecy quietly failed?

Who Is Plan B and Why Should You Care?

Operating under the mysterious handle Plan B, this anonymous quant first gained mainstream attention in March 2019 with a Medium article titled "Modeling Bitcoin's Value with Scarcity." The post introduced a quantitative framework that mapped Bitcoin's stock-to-flow ratio — a measure of scarcity borrowed from commodities markets — to its market value.

Unlike countless other crypto commentators, Plan B built credibility through rigorous data analysis rather than hype. The model was backtested against historical data, showing an R² value (a statistical measure of fit) of over 0.95, meaning Bitcoin's price followed the S2F curve with remarkable accuracy across multiple market cycles.

The model's appeal lies in its simplicity. By treating Bitcoin as a digital commodity with predictable issuance, Plan B offered something the crypto space rarely delivers: a long-term valuation framework divorced from day-to-day sentiment, influencer narratives, and short-term volatility.

Breaking Down the Stock-to-Flow Model

Stock-to-flow is a ratio used traditionally to assess commodities like gold and silver. It compares the existing supply (stock) to the new production (flow). The higher the ratio, the scarcer the asset, and — according to Plan B's framework — the higher the price.

  • Gold's S2F: approximately 60
  • Silver's S2F: approximately 30
  • Bitcoin's S2F after the most recent halving: roughly 120

Plan B's central thesis argues that as Bitcoin's halvings cut new supply in half every four years, the asset becomes increasingly scarce — and scarcity drives price. Each halving event theoretically catapults Bitcoin onto a higher valuation curve, with the model forecasting specific price ranges for each cycle.

The Halving Effect in Plain English

Every 210,000 blocks — roughly every four years — Bitcoin's block reward gets cut in half. This programmed scarcity is hardcoded into the protocol and cannot be changed without overwhelming network consensus. The S2F model treats this predictable supply shock as the primary driver of long-term price appreciation, ignoring much of the day-to-day noise that consumes crypto Twitter.

Plan B's Bold Bitcoin Price Predictions Through the Years

The original S2F model suggested Bitcoin could reach $55,000 by 2021 and eventually touch $1 million per coin by 2025. While the $55,000 target was famously hit — and surpassed — during the 2021 bull run, the million-dollar prediction remains a work in progress and a frequent target of skeptics.

Plan B later introduced an updated S2F cross-asset (S2FX) model, which treats Bitcoin as part of a broader evolution — from a collectible, to digital gold, to a global monetary asset. This updated model includes time and other asset classes, providing a more nuanced view of where Bitcoin sits in its lifecycle relative to gold, silver, and other stores of value.

"Bitcoin is the first scarce digital object the world has ever seen. It is digital gold." — Plan B

The S2FX model also projected that Bitcoin's market capitalization could eventually rival — or even surpass — gold's, currently measured in the tens of trillions. That alone would imply a price per coin well into six-figure territory, even after recent price action.

Criticisms: Does the Model Still Hold Up?

No model is bulletproof, and the S2F framework has faced serious scrutiny from academics, traders, and rival analysts. Critics point out that correlation does not equal causation, and the model's tight historical fit may be a case of curve-fitting rather than genuine predictive power.

Notable critiques include:

  • The 2022 crypto winter saw Bitcoin drift significantly below S2F projections for extended periods
  • Macroeconomic factors like interest rates, dollar liquidity, and global risk appetite may matter more than scarcity alone
  • The model cannot account for black swan events such as exchange collapses, regulatory shocks, or stablecoin de-pegging
  • Many competing models exist that fit historical data just as well but offer different price targets

Even Plan B himself has acknowledged that the model works best over multi-year time horizons, not short-term trading windows. The takeaway? S2F is a macro framework, not a trading signal — a thermometer, not a crystal ball.

Why Plan B's Bitcoin Thesis Still Resonates

Despite the criticism, the core idea remains compelling. With the most recent halving now baked into the supply schedule, Bitcoin's stock-to-flow ratio has climbed to new highs, putting it squarely in "digital gold" territory by any traditional commodity standard.

For long-term believers, the message is simple: scarcity plus adoption equals value. Institutional inflows via spot Bitcoin ETFs, nation-state adoption discussions, and the ongoing de-dollarization narrative all align — at least philosophically — with Plan B's original thesis about Bitcoin becoming the ultimate hard money of the digital age.

Key Takeaways

  • Plan B is a pseudonymous analyst whose Stock-to-Flow model treats Bitcoin as digital scarcity
  • The S2F model maps Bitcoin's programmed halvings to long-term price trajectories with high historical fit
  • Predictions have ranged from $55,000 (hit) to $1 million per coin (still pending)
  • Criticisms include curve-fitting concerns and an inability to capture macro shocks
  • The model is best used as a long-term valuation lens, not a short-term price prediction tool

Whether Plan B's Bitcoin model proves prophetic or merely poetic, it has fundamentally shaped how a generation of investors thinks about digital scarcity. In a market drowning in noise, that alone is a remarkable legacy.