Why a miner mined an empty block at height 960,017

Bitcoin block 960,017 was mined early on Tuesday, July 28, at roughly 02:28 UTC, and it contained exactly zero user transactions. The only thing inside it was the coinbase transaction — the entry that pays the miner its block reward. Fee revenue for the block: nothing.

That sounds like a malfunction and is not one. It is a well-documented behaviour of how pools hand work to machines, and it happens for a reason that takes about two seconds to occur and about two minutes to understand.

When a new block appears on the network, every pool wants its machines hashing on the next one immediately. Building a full template — selecting transactions from the mempool, verifying they are still valid after the block that just landed, assembling the Merkle tree — takes work and produces a larger payload to push out to thousands of machines. So pools send two templates in sequence: first a stripped one with no transactions, which is tiny and arrives instantly, then the full one a moment later.

Machines start hashing the empty template the instant it arrives. Almost always the full template lands before anyone gets lucky, and the block that eventually gets found is a normal full one. Occasionally, inside that one-to-two-second window, a machine finds a valid hash anyway. The block it submits is the one it was holding: empty. That is block 960,017.

The arithmetic behind the choice is not close. The subsidy is currently 3.125 BTC, worth roughly $200,000 at present prices, while a typical block's fees at current mempool levels run in the low hundreds of dollars. A pool that made its machines idle for two seconds after every block, to guarantee it never shipped an empty one, would be trading a small, certain loss of hashing time against a rounding error. No rational operator takes that trade — which is why this behaviour is universal rather than a quirk of one pool.

Attribution for this particular block is unsettled. One report suggests F2Pool, but the block has not been firmly attributed at the time of writing, and we are not treating the label as established. What is verifiable is the pattern: SpiderPool produced the previous notable empty block at height 954,352 on June 19, weighing barely over a kilo weight-unit. Empty blocks exceeded ten percent of all blocks in Bitcoin's early years; today they run under one percent, largely because of faster propagation techniques such as compact blocks and better pool software.

Nothing was lost by anyone else. No transaction was dropped, reversed, or delayed beyond the next block a few minutes later — the mempool simply held its queue. The difficulty adjustment does not care whether a block was full, so issuance continued exactly on schedule. There was no market reaction, and there should not have been one: the only party out of pocket is the miner that forfeited a block's worth of fees for the privilege of never letting its machines rest.

BITCOIN ALMANACK ANALYSIS

Block 960,017 against a normal block

Transaction counts and fee levels are typical ranges at current mempool conditions · Table: Bitcoin Almanack

WHY IT MATTERS

Empty blocks are a useful stress test of your own mental model. If one makes you nervous, the thing to examine is the assumption that every block must be full for the system to be working. Bitcoin's guarantee is that valid blocks extend the chain on schedule — not that any particular block carries your payment. The queue is the mempool's job; the clock is the network's.

SOURCES & DATA

Crypto Briefing — report on block 960,017, timestamp and zero-fee detail ↗ mempool.space — block 960,017, verify transaction count and coinbase yourself ↗ BitcoinWiki — empty block reference ↗

The mining entity behind this block is single-sourced and unconfirmed; we describe it as unattributed rather than naming a pool. Subsidy value converted at the prevailing spot price. See our editorial process and corrections policy.

Aisha Bennett

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