Roughly every four years, Bitcoin's halving cuts the block subsidy in half, slashing miner revenue per block overnight. The adjustments that follow — in hash rate, difficulty, and miner selling — ripple through supply dynamics in ways worth tracking on a desk.

The revenue shock

Miners earn the block subsidy plus transaction fees. The halving cuts the subsidy in half instantly, so unless price or fees rise to compensate, miner revenue per unit of work drops sharply. For miners running at thin margins, the same electricity and hardware now produce half the coin reward.

This is a real economic shock to the mining industry, and how it resolves shapes near-term supply.

Hash rate and difficulty adjust

The network self-corrects through two linked mechanisms:

  1. Marginal miners capitulate. Those whose costs now exceed revenue switch off, especially older, less efficient hardware. Hash rate — total mining power — can dip as they leave.
  2. Difficulty adjusts. Bitcoin retargets mining difficulty roughly every two weeks to keep block times near ten minutes. As miners drop off, difficulty falls, which lowers costs for the survivors and restores their margins.

The result over time is a reshuffling toward efficient miners and cheap power, with hash rate typically recovering as the industry rebalances. The transition can be choppy.

Miner selling pressure

For supply, the key variable is miner selling. Miners must cover costs in fiat, so they sell a portion of their coin. Watching miner flows matters because:

  • Post-halving margin stress can force selling from weaker miners liquidating reserves to survive — short-term supply pressure.
  • Stronger miners may hold or even accumulate if they expect higher prices, withholding supply.
  • The net effect depends on the balance between distressed selling and confident holding.

On-chain, miner outflow and miner reserve metrics track this. A spike in miner outflows during post-halving stress is supply hitting the market; a decline in selling as efficient miners stabilise removes a headwind.

What desks watch

Practically, the post-halving checklist:

  • Hash rate trajectory — capitulation and recovery signal where the industry shakeout stands.
  • Difficulty adjustments — the self-correcting mechanism restoring margins.
  • Miner reserve and outflow metrics — the actual supply-side pressure, filtered for custody noise.
  • Fee revenue — as the subsidy shrinks over successive halvings, fees become a larger share of miner income, and their level matters more each cycle.

Beware over-reading any single metric: miner flows are noisy and easily distorted by custody and OTC movements.

Takeaway

The halving halves miner revenue overnight, forcing marginal miners off, which lowers hash rate until difficulty adjusts down and restores survivors' margins. The supply-relevant variable is miner selling: distressed miners liquidating versus efficient ones holding. Watch hash rate, difficulty, miner reserves and outflows, and the rising importance of fee revenue — while filtering miner-flow data for custody noise.