Understanding the Stock to Flow Ratio
The Stock to Flow (SF or S2F) model measures the abundance of a resource by comparing its existing stock (total supply) to its annual flow (new production). This ratio helps assess how稀缺 a resource is—a higher ratio indicates better value retention over time.
Calculating Stock to Flow: The Gold Example
- Stock (Total Supply): ~190,000 tons of gold mined historically (World Gold Council estimate).
- Flow (Annual Production): 2,500–3,200 tons/year.
- Ratio: ~59 (190,000 ÷ 3,200). This means it would take 59 years to reproduce the current stock at today’s production rate.
Bitcoin as a Digital Scarce Resource
Bitcoin shares key traits with黄金:
- Fixed Supply: Capped at 21 million BTC.
- Predictable Flow: Halvings every 4 years reduce new supply (e.g., 2020 halving cut block rewards from 12.5 to 6.25 BTC).
- Current S2F Ratio: ~25 (18M circulating supply ÷ 0.7M new BTC/year). Post-2020 halving, it jumped to ~50.
Historical Price Correlation
A 365-day moving average shows Bitcoin’s price trends align with S2F projections. Halvings (vertical axis events) often precede bull markets.
| Event | S2F Ratio | BTC Price Impact |
|---|---|---|
| 2012 Halving | ~25 → ~50 | 100x Increase |
| 2016 Halving | ~50 → ~100 | 30x Increase |
Critiques and Limitations
- Assumption Dependency: S2F presumes scarcity alone drives value—ignoring utility, adoption, or regulatory risks.
- Volatility: Bitcoin’s macro volatility may decline (per historical data), but micro spikes remain due to low liquidity and speculative trading.
- Black Swan Events: Unpredictable crises (e.g., pandemics, exchange hacks) can disrupt models relying on historical data.
FAQs: Addressing Common Queries
Q: Can Bitcoin’s S2F ratio surpass gold’s?
A: Yes. Post-2140 (when all BTC are mined), Bitcoin’s flow drops to zero, making its S2F ratio theoretically infinite.
Q: Does S2F account for lost coins?
A: No. The model treats lost BTC (estimated 3–4M) as part of the stock, potentially overstating scarcity.
Q: Why might S2F fail for Bitcoin?
A: If demand falters (e.g., due to competition from other cryptos or regulatory bans), scarcity won’t guarantee value.
Key Takeaways
- Scarcity ≠ Value: S2F is a useful metric but incomplete without demand-side analysis.
- Long-Term Trends: Bitcoin’s programmed supply cuts align with historical price appreciation.
- Caution: Models simplify reality—diversify research methods before investing.