Bitcoin’s Fourth Halving Reached Its First-Year Mark With Miners Under Pressure

On April 20, 2025, Bitcoin completed the first calendar year of its fourth block-subsidy era. The protocol had continued issuing 3.125 new bitcoin for each valid block, half the 6.25 BTC subsidy that applied before block 840,000 was mined on April 20, 2024.

The anniversary mattered less as a ceremonial date than as a clean checkpoint. Halvings are often presented as automatic catalysts for price appreciation, but the first year of this cycle produced a more complicated record: bitcoin’s dollar price was higher, computational competition had intensified, and miners were earning substantially less revenue for each unit of hash power they deployed.

What the protocol changed

Bitcoin’s block record identifies height 840,000 as the first block under the 3.125 BTC subsidy. The scheduled reduction did not remove transaction fees, change the 21 million supply limit or guarantee that blocks would arrive at exact ten-minute intervals. It changed the new-coin component of miner compensation according to a rule enforced by participating nodes.

At Bitcoin’s targeted average of 144 blocks per day, the subsidy reduction lowered theoretical new issuance from about 900 BTC to 450 BTC per day. Those are protocol-rate calculations—144 multiplied by the applicable subsidy—not measurements of the number of coins actually produced on every calendar day. Block production varies, and fees are separate from newly issued bitcoin.

That distinction is central to evaluating the anniversary. The halving made issuance scarcer by rule, but it did not dictate demand, exchange liquidity, energy prices, equipment efficiency or the dollar value of the remaining subsidy.

The market checkpoint

Yahoo Finance’s retrospective BTC-USD daily series records an April 20, 2025 open of $85,066.07, a high of $85,306.38, a low of $83,976.84 and a close of $85,174.30. The comparable April 20, 2024 close in the historical series was approximately $64,994.44. Using those two daily closes, Coinburn calculates an increase of about 31.0%.

That comparison is descriptive, not causal. Bitcoin trades continuously across venues, so a daily “close” is an aggregation convention rather than an official auction price. The selected BTC-USD series and its UTC-style daily boundary may differ from the CME CF Bitcoin Reference Rate, individual exchange candles or the price at the precise timestamp of block 840,000. The calculation therefore does not establish that the halving caused the gain.

Mining competition intensified

The network’s April 19, 2025 difficulty adjustment—one day before the anniversary—increased difficulty by 1.42% to 123.23 trillion, then a record, according to Hashrate Index’s April 21 mining report. Difficulty measures how hard it is, under the protocol target, to find a valid block relative to Bitcoin’s original baseline. A rising value indicates greater aggregate competition for the same scheduled subsidy, not that every miner added equipment or remained profitable.

Hashrate Index measured the seven-day simple moving-average network hashrate at 867 exahashes per second for its April 14–21 window, down 3.88% across that particular week. It placed dollar-denominated hashprice at $45.08 per petahash per second per day on April 21. Hashprice is an estimated revenue rate, not a universal profit figure; electricity contracts, machine efficiency, curtailment, financing, pool fees and facility costs differ by operator.

What the anniversary established

The April 20, 2025 record supported two conclusions. Bitcoin’s programmed issuance reduction operated as designed, while market price appreciation did not spare miners from stronger competition and compressed unit economics. It did not prove a recurring four-year price pattern or establish that price, hashrate and difficulty would continue rising together.

Later analysis published by Fidelity Digital Assets on May 22, 2025 estimated that hashprice had fallen roughly 60% since April 2024 while 30-day mean hashrate and difficulty had increased roughly 40%. That retrospective evidence clarifies the first-year pressure on miners, but it was not available on April 20 and should not be treated as contemporaneous commentary from the anniversary date.