Bitcoin halving and bull markets: evidence from four halvings

What the protocol actually changes

Bitcoin’s scheduled halving reduces the block subsidy, the newly issued coins available to miners per block. It does not halve existing balances, total circulating supply or transaction fees. The subsidy schedule is a supply rule; a market price also depends on demand, existing holders’ transactions and expectations.

The event is scheduled by block height, so the calendar date is estimated until the relevant block arrives. A widely anticipated supply change can affect expectations before its effective date. A price reaction need not begin on the halving day, and a supply change alone does not specify its direction or size.

A consistent comparison, including the uncomfortable parts

We recalculated the table from Coin Metrics’ public BTC PriceUSD daily series, using the UTC halving dates listed by Bitcoin.org. The comparison uses the same 30-day and 365-day offsets for every event, rather than selecting each cycle’s best exit. The preceding 365-day return is included to show that substantial changes can occur before the event.

Every one-year endpoint is positive here. Yet 2016 is negative over the first 30 days, and the four one-year paths contain maximum drawdowns ranging from about 25.55% to 71.24%. A positive endpoint therefore does not mean a smooth rise or an absence of large interim losses. These are price observations without trading costs, not account returns.

How the numbers were calculated

For each event date t, the endpoint return is 100 × (P[t + h] / P[t] − 1). PriceUSD represents the UTC day-end closing price for the labelled date, not the exact halving-block price. The one-year path includes the event-day close and the following 365 daily closes: 366 positive, non-missing observations per event. No missing date was interpolated.

Maximum drawdown is the most negative value of 100 × (daily price / the running maximum since the event-day close − 1). It measures peak-to-trough loss within that path. It is different from the minimum return relative to the event date, and daily closing prices can miss larger intraday losses.

Why four positive outcomes do not identify a cause

The independent event count is four, not the number of daily rows. Bitcoin’s market size, ownership, infrastructure and macroeconomic environment changed between cycles. There is no observed version of the same market in which the scheduled halving did not occur, and this table does not control for those other changes.

The historical pattern is compatible with a contribution from reduced issuance, but it cannot assign a causal percentage to that mechanism. It also cannot establish a universal rule for altcoins or the entire crypto market. An event chosen for a familiar narrative must not be treated as a random, independent experiment.

What a stronger study would add

A stronger design would predefine observation periods, compare non-halving dates under comparable market conditions, test sensitivity to dates and sources, and incorporate demand and miner-flow evidence. Those controls are not included here. The defensible conclusion is that historical cycles deserve study, while “halving guarantees a bull market” goes beyond the evidence.

Does Bitcoin always go up after a halving?

All four events in this historical sample have positive 365-day endpoint returns, but shorter observations and interim drawdowns differ. Four selected events cannot establish an always-rising rule or guarantee the next cycle.

Does Bitcoin halving alone cause a crypto bull market?

The comparison does not isolate that causal effect. A scheduled supply change occurs alongside changes in demand, liquidity, access and wider financial conditions. Those influences cannot be separated with four event comparisons alone.

Limitations

Four historical events, retrospective observation periods and daily closing prices. No causal counterfactual, matched-control study, intraday path or predictive validation is supplied. The raw source can be revised; its fingerprint identifies the snapshot used.

Sources and data access

• Bitcoin.org: halving history and block-subsidy mechanism
• Coin Metrics: public BTC daily data
• Coin Metrics: PriceUSD definition and timestamp convention

Cited sources document external facts or data formats; they do not endorse our findings. The public snapshot contains the table and methods. Source-file fingerprints are included for recalculated datasets. Full archived raw files are not distributed here; fingerprints identify the files used, rather than independently proving the results.

Aggregate data snapshot (JSON) · Markdown · Methods and limitations

Live prior 30-day hourly baseline — separate from the historical study

Only the current watch list is shown, up to 12 assets. Missing or stale estimates remain unavailable. Venue and quote currency are kept separate; beta needs matching BTC data. Hourly statistics are not minute-move probabilities.

Observation cutoff (UTC): 20/10/2026, 14:59

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