How this Rainbow Chart is calculated
The browser requests BTCUSD end-of-day prices from July 2010 onward. It filters unusable dates and nonpositive prices, keeps one observation per returned date and fits log10(price) = a × log10(days since genesis) + b by least squares. Availability is limited to the returned data; no prehistory is fabricated.
Nine bands surround the curve. Adjacent boundaries differ by 0.42 log10 units, a display choice with no statistical coverage interpretation. Prices outside all bands are labeled outside the range rather than assigned a buy or sell signal.
Read the sample before reading the colors
- Check the first and last observation dates. The latest historical observation is not a live quote.
- Inspect the displayed fitted coefficients and sample size. Revisions or a changed history window can move every band.
- Use the curve-extension control to see extrapolation sensitivity. Extending a mathematical curve is not evidence of future returns.
- Treat halving markers as context only. The fit does not isolate halving effects from other causes.
What the model cannot establish
This is an in-sample descriptive visualization. It contains no out-of-sample test, cash-flow valuation, market-sentiment measurement or profitable trading rule. A line fitted using future observations cannot be treated as a signal that was available earlier in history.
Method reference: NIST on least-squares fitting and extrapolation limits. Bitcoin subsidy timing is documented in Bitcoin Core mainnet parameters.