A major Japanese Bitcoin mining pool just pulled the plug on its Bitcoin service just as 3 mega-miners claimed 60% of the network

By the time SBI Crypto pulled the plug on its Bitcoin pool in Japan on July 31, its seven-day average hashrate had fallen 64% in a month. Later that day, a Hashrate Index reading put Foundry USA, AntPool and F2Pool at 60% of recent blocks. The timing makes them look connected. Weekly data tell a messier story.

SBI Crypto's official update set the first cutoff at 22:00 UTC on July 30, or 07:00 JST on July 31. Share acceptance stopped, and miners began a graceful disconnect. The company scheduled a full Stratum shutdown by 23:59:59 UTC. Its website would stay open for historical data and payout status. The final payout schedule remained unspecified, as did the end dates for API and portal access.

At about 11:22 UTC on July 31, Foundry held 26.67% of attributed blocks, AntPool 17.13% and F2Pool 16.21%. SBI Crypto was down to 0.72%, or an estimated 6.8 exahashes per second. The dashboard moved again within minutes. The 60.01% reading captures a moment, rather than a lasting level of control.

SBI Crypto's daily telemetry charted a month-long retreat. Its seven-day average BTC hashrate dropped from 16.222 EH/s for the period ending June 30 to 5.817 EH/s for the period ending July 30. By 11:17 UTC on July 31, separate operational statistics put the 24-hour average at about 0.452 EH/s. SBI's official block list showed July 29 as its latest block.

Matched weekly buckets from mempool.space put Foundry, AntPool and F2Pool at a combined 64.8039% for July 20, then 60.7843% in the still-incomplete July 27 bucket. SBI Crypto's share fell from 0.9804% to 0.6192%. The top tier had cleared 60% before the cutoff. The July 27 bucket spans the shutdown and remains incomplete, leaving any immediate concentration effect unmeasured.

Individual pool movements pulled in different directions. Foundry, AntPool and F2Pool each showed lower estimated hashrate in the partial July 27 bucket than in the prior week.

Luxor rose, Braiins fell, and NeoPool was absent. Pool-share records reflect work credited to a service.

Thus, the routes behind SBI Crypto's lost pool hashrate stay hidden in these aggregate totals.

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