SBI Crypto has ended its Bitcoin mining pool service, coinciding with a period when three major mining pools collectively controlled 60% of the network's hashrate, raising new questions about centralization risks for Bitcoin.
SBI Crypto, a prominent Japanese Bitcoin mining pool, has discontinued its Bitcoin mining service as of July 31, 2026. The move comes at a time when network concentration is drawing renewed scrutiny, with three mega-miners-Foundry USA, AntPool, and F2Pool-briefly accounting for 60% of Bitcoin's total hashrate. The timing of SBI Crypto's exit has intensified concerns about the distribution of mining power and the potential implications for Bitcoin's security and decentralization.
Rapid Decline and Shutdown Timeline
According to an official update from SBI Crypto, the pool began winding down operations at 22:00 UTC on July 30, with share acceptance ceasing and miners disconnecting in a phased process. The company scheduled a complete shutdown of its Stratum server by the end of July 31 UTC. While the website remains accessible for historical data and payout status, SBI Crypto has not specified the final payout schedule or the end dates for API and portal access. The shutdown followed a sharp drop in the pool's seven-day average hashrate, which fell 64% over the month leading up to the closure-from 16.222 exahashes per second (EH/s) at the end of June to 5.817 EH/s by July 30. By the morning of July 31, the pool's 24-hour average hadhrate had plummeted to just 0.452 EH/s, and its last mined block was recorded on July 29.
Network Concentration and Market Impact
On the day of SBI Crypto's shutdown, data from Hashrate Index showed Foundry USA, AntPool, and F2Pool collectively responsible for 60.01% of recently mined blocks. At 11:22 UTC, Foundry USA held 26.67% of attributed blocks, AntPool 17.13%, and F2Pool 16.21%. SBI Crypto's share had dwindled to 0.72%. While this 60% figure represents a snapshot rather than a sustained level, it highlights the ongoing risk of mining centralization. Weekly data from mempool.space indicated that the top three pools had already surpassed the 60% threshold before SBI Crypto's exit, with their combined share reaching 64.8% for the week ending July 20 and 60.8% in the partial week ending July 27. The incomplete data for the shutdown week leaves the immediate impact of SBI Crypto's departure on network concentration uncertain.
Hashrate Redistribution and Unanswered Questions
Not all of SBI Crypto's lost hashrate appears to have flowed directly to the largest pools. During the shutdown period, Foundry USA, AntPool, and F2Pool each reported lower estimated hashrate in the partial July 27 week compared to the previous week. Meanwhile, Luxor's share increased, Braiins declined, and NeoPool was absent from the data. Because pool-share statistics reflect only credited work, the ultimate destination of SBI Crypto's former hashrate remains unclear. This opacity complicates efforts to assess whether the shutdown has further concentrated mining power or simply redistributed it among smaller pools. The episode echoes broader industry concerns about the sustainability of large-scale mining operations, as seen in recent shifts by U.S. mining firms toward alternative revenue streams.
Key Metrics and Industry Context
As of July 31, 2026, Bitcoin's global hashrate was estimated at over 500 EH/s, with the top three pools controlling a combined 60% of block production during the shutdown window. SBI Crypto's share had dropped below 1% by the time of its exit. The company has not disclosed the number of miners or users affected, nor has it provided a timeline for final payouts. The concentration of mining power among a handful of pools remains a focal point for both industry participants and observers concerned about Bitcoin's long-term resilience.
Mining pool concentration is a persistent challenge for proof-of-work blockchains like Bitcoin. When a small number of pools control a majority of the network's hashrate, the risk of coordinated action-such as transaction censorship or reorganization-increases, even if only in theory. While individual miners can switch pools, the underlying incentives and operational realities often favor larger, more established pools due to economies of scale, lower fees, and more consistent payouts. This dynamic can make it difficult for new or smaller pools to gain traction, reinforcing existing power structures and raising questions about the future of decentralized mining.
