Solo miners have been defying the odds, successfully claiming full Bitcoin block rewards even as the network hashrate hovers near all-time highs.

As of this writing, the Bitcoin (BTC) network’s hashrate is hovering around 902 exahashes per second (EH/s), just below its all-time peak, according to Blockchain.com. The figure shows growing competition and higher difficulty, suggesting that single miners face steep odds to win a block.

However, last week, a solo miner defied these odds, securing block 907,283 via the Solo CK pool and earning the full 3.125 BTC reward, worth over $372,000 at the time. The miner also received an additional $3,436 in transaction fees.

That win wasn’t an isolated event. Earlier in July, another miner with just 2.3 petahashes of power claimed a full block reward, while similar wins were recorded in June, March and back in February.

“We’re seeing solo miners win blocks not because of luck, but because they’re running powerful, efficient hardware,” Samuel Li, chief technology officer of ASICKey, told Cointelegraph. He added that modern miners are built to deliver “serious hashrate” without the massive power draw of traditional setups.

Related: Solo Bitcoin miner scores $373,000 block reward

Efficiency in focus

For solo miners, efficiency is everything, Li said. “Take our KEYMINER A1—it draws just 650 watts but delivers 1,100 TH/s on Bitcoin, with monthly profits around $1,200. For those diversifying into altcoins, it can earn up to $3,800 per month mining Dash,” he noted.

The KEYMINER A1 is part of ASICKey’s hardware line introduced last November, which also includes the KEYMINER X and KEYMINER PRO.

However, despite the improvements in application-specific integrated circuit (ASIC) efficiency, the “fundamental odds [of solo miners winning] haven’t shifted much,” Li said.

“Solo mining is still mostly a lottery, unless you control tens of PH/s, which is realistically the bare minimum for having a measurable statistical shot at success within a reasonable time frame,” he added.

Li explained that at today’s Bitcoin network hashrate, a miner with one petahash (PH/s) of hashpower has about a 1 in 650,000 chance of solving a block every 10 minutes. One peta hash (PH/s) is equivalent to 1,000 terra hashes (TH/s).

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Why are miners going solo?

Li confirmed that there has been a “modest resurgence” of interest in solo mining, but for different reasons. “Some miners are choosing it not for predictable income, but for the possibility of a big reward—6.25 BTC plus fees—which can be transformative if won,” he noted.

While monetary incentives play a key role, some are driven by ideological motives, valuing network decentralization and the ability to operate independently of centralized mining pools.

According to data from Hashrate Index, US-based mining pool Foundry USA continues to dominate Bitcoin mining, commanding 29.3% of the total hashrate. AntPool follows with 16.2%, while ViaBTC and F2Pool hold 12.0% and 11.6% respectively.

If a single pool (or a few pools acting together) control more than 50% of the hashrate, they could theoretically launch a 51% attack, which would allow them to double-spend coins. While rare and costly, such an event would erode trust in the network.

“Ultimately, more solo miners—especially those operating on clean energy and efficient hardware—could represent a healthier, more decentralized Bitcoin network, which is aligned with the original vision of permissionless participation,” Li concluded.

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