Bitcoin’s Third Halving Cut the Block Subsidy to 6.25 BTC

Bitcoin activated its third subsidy halving at block 630,000 on May 11, 2020, reducing the maximum newly issued reward for each valid block from 12.5 BTC to 6.25 BTC. The event was consequential because it changed miner revenue and Bitcoin’s issuance rate through an existing consensus rule, without a regulator, company or network administrator making a discretionary decision.

The block’s header carries a timestamp of 19:23:43 UTC. Its hash was `000000000000000000024bead8df69990852c202db0e0097c1a12ea637d7e96d`. Public explorers attribute it to AntPool from identifying data in the coinbase transaction, although pool attribution is not itself a cryptographic proof of corporate identity.

Block 630,000 contained 3,134 transactions and 0.90968084 BTC in transaction fees. Its miner could therefore claim 7.15968084 BTC: the new 6.25 BTC subsidy plus the recorded fees. The preceding block remained under the 12.5 BTC subsidy schedule.

A consensus rule, not a software launch

Bitcoin Core 0.19.1, the contemporaneous implementation reviewed for this reconstruction, set the main-network subsidy-halving interval at 210,000 blocks. Its subsidy function began from 50 BTC and shifted that amount downward according to the number of completed 210,000-block intervals.

At height 630,000, three complete intervals had elapsed. The resulting calculation was 50 divided by eight, or 6.25 BTC. Nodes enforcing the existing rules would reject a block whose coinbase transaction claimed more than the permitted subsidy and fees.

That distinction mattered on May 11. The halving was not an update that users needed to install at block 630,000, and it did not alter previously issued bitcoin. It changed the maximum subsidy available from that height onward.

At Bitcoin’s target pace of one block every ten minutes, the theoretical scheduled issuance rate fell from approximately 1,800 BTC to 900 BTC per 24 hours. Those figures are calculations using 144 blocks per day, not measured daily totals. Actual issuance varies because proof-of-work blocks do not arrive at perfectly regular intervals.

Markets had anticipated the event

The known schedule did not produce a mechanical price increase. Reuters reported that bitcoin was down 1.3% at $8,620.43 on Bitstamp in late-afternoon New York trading on May 11, after briefly turning positive. That was a venue-specific point-in-time quotation, not a consolidated global close for an asset trading continuously across exchanges.

The market surrounding the third halving was also more institutionalized than during the 2012 and 2016 reductions. CME Group reported that open interest in its five-bitcoin futures contract reached a then-record 8,706 contracts, with approximately $407 million in notional value, on May 6. Futures and options allowed participants to hedge or express views on bitcoin without relying exclusively on spot holdings.

Open interest measured outstanding contracts, not the number of distinct investors or a directional forecast. It nevertheless established that the halving arrived amid substantial regulated derivatives positioning.

The immediate test shifted to miners

The subsidy reduction immediately halved the bitcoin-denominated fixed revenue available for finding a block. Transaction fees remained additional compensation, but block 630,000 demonstrated their limited cushioning effect: its 0.90968084 BTC in fees replaced only part of the 6.25 BTC subsidy reduction.

The effect on individual operators could not be determined from the block alone. Electricity prices, hardware efficiency, financing, pool arrangements, uptime and hedging differed across miners. A less-efficient machine could become uneconomic while newer equipment remained viable.

The defensible May 11 conclusion was therefore narrow. Bitcoin executed its programmed third halving without an interruption documented in the reviewed records, and the permitted subsidy fell exactly as the contemporaneous code prescribed. The event established a new issuance schedule; it did not establish the future price of bitcoin, the profitability of every miner or the longer-term security budget of the network.