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Bitcoin climbs to $21,500 (+5% daily) amid fresh attacks on the stock‑to‑flow model; see why analysts doubt its price forecasts and what to watch next.
Bitcoin jumped 5% to around $21,500 in a single day, reviving debate over the stock‑to‑flow (S2F) model that once projected $100,000‑plus prices for 2022 – 2024 [2]. The move underscores how price swings now test the model’s credibility, a point highlighted by Ethereum co‑founder Vitalik Buterin and PlanB’s own defenses.
| At a glance | |
|---|---|
| Price | $21,500 |
| 24h change | +5% |
| Key level | $20,000 support |
| Catalyst | Market bounce after 18‑month low, renewed S2F criticism |
The 5% rally lifted Bitcoin from an 18‑month trough below $20,000, a level that had anchored the market since late 2022 [2]. The bounce came as the crypto community revisited the S2F model, which links Bitcoin’s scarcity (stock) to its annual new supply (flow). PlanB’s original curve predicted $100,000‑$110,000 for 2022, yet the asset lingered under $20,000 through most of 2023 [2]. Critics, led by Buterin, argue the model offers “false certainty” and is unfalsifiable because any price movement can be retro‑fitted to the curve [2].
PlanB responded that the recent slump merely created scapegoats for failed projects, insisting the model performed well from March 2019 to March 2022 [2]. He now suggests Bitcoin is either “extremely undervalued” and poised to rebound, or the S2F framework will lose relevance [2]. The ongoing debate reflects a broader shift: institutional inflows via spot ETFs have altered demand dynamics, a factor the original S2F math did not consider [4].
The S2F ratio rose above gold’s after the 2024 halving reduced the block reward to 3.125 BTC, making Bitcoin the “scarcest liquid asset” as of early 2026 [4]. While scarcity is indisputable, the model’s price forecasts have repeatedly missed, notably the missed $100,000 target for 2022 and the unrealized $288,000 ceiling for 2024 [2]. Analysts point to demand‑side variables—ETF purchases, corporate balance‑sheet holdings, and sovereign reserve allocations—that the S2F formula ignores [4].
The latest price surge highlights the tension between a mathematically elegant scarcity narrative and the messy reality of demand‑driven price formation. Whether the S2F model will adapt or fade remains an open question for investors tracking Bitcoin’s next moves.
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AI-assisted synthesis by the TrendWatcher Editorial Desk · sourced from 4 outlets · Jul 29, 2026 · How we report
It is a mathematical ratio calculated by dividing the total existing supply of an asset (stock) by the amount of new supply produced annually (flow).
Halving events reduce the block reward for miners by 50%, which lowers the annual flow of new Bitcoin and increases the S2F ratio, theoretically signaling higher scarcity.
While it was influential in earlier cycles, its predictive accuracy has weakened as Bitcoin's price has frequently deviated from the model's projections, leading many to use it as a historical reference instead.
The model is applied because Bitcoin has a limited, code-defined supply schedule, making it comparable to scarce physical commodities like gold.