Research briefing
Reading the halving-window record without overfitting it
- Written by
- The Bitcoin Data Guide editorial team
- Reviewed by
- Data review desk
- Dates
- Published 30 September 2026
Fact
Every figure in this briefing is drawn from the site's canonical dataset as it stood on 30 September 2026.
Forecast
Any forward-looking framing in this note is interpretation, not a measured outcome, and is labelled as such.
What changed since the previous briefing
This note follows Drawdown recovery durations: the deepest declines took two to three years, filed on 31 August 2026. The sections below record what moved in the data or the research between the two dates.
The record
The four block-subsidy halvings occurred on 2012-11-28, 2016-07-09, 2020-05-11 and 2024-04-20, at block heights 210,000, 420,000, 630,000 and 840,000. The subsidy fell from fifty bitcoin to twenty-five, then to 12.5, then to 6.25, and then to 3.125. The fifth halving is scheduled at block 1,050,000.
The measurement
The post-halving window series starts at the year-end close of the calendar year in which the halving occurred and runs forward a fixed number of months on the annual observation grid. A window that would extend past the end of the series is cut short at the last available observation and flagged as truncated, so a truncated entry is not a full-length measurement.
The limitation
Four events cannot distinguish a halving effect from the market conditions that happened to surround each one. The series is published as a dated record of what followed each halving, not as a forecast of what the next one will produce.
Datasets this briefing draws on
- halving-history
- yearly-returns
Sources
- halving-history
- A curated dataset this briefing draws on.
- yearly-returns
- A curated dataset this briefing draws on.