In brief Unknown miners now contribute more than half of the Bitcoin SV network hash rate.

Coingeek has seen its popularity as a mining pool decline significantly in the last week.

There is a possibility this change could represent an impending 51% attack.

A mysterious mining pool has just captured the majority of the Bitcoin SV (BSV) network hash rate, prompting concerns about the security of the network.

According to data by Coin Dance, an unknown Bitcoin miner, or miners, has significantly ramped up mining operations on the Bitcoin SV blockchain in the last few days. This now accounts for more than half of the Bitcoin SV hash rate—computing power that secures the network.

As of yesterday (March 23), unknown miners contributed a total of 1,576 PH/s of mining power, up from 730 PH/s just a week earlier—a 100% increase.

Around the same time, a large amount of hash rate departed from Coingeek—a company that advocates for Bitcoin SV. It’s seen a 75% drop in the last week.

It’s possible that some of the miners have decided to move from Coingeek to another mining pool. But there are some differences. The unknown mining hash rate no longer processes transactions for the weather app that accounts for the majority of BSV transactions.

Since this mining entity now controls more than 50% of the Bitcoin SV network, it could—theoretically—launch a type of attack known as a 51% attack, which can cause all sorts of issues. If a 51% attack were launched, the attacker could do things like rewrite recently confirmed blocks, block transactions from confirming and double-spend recent transactions.

This is now the second time in three months that the Bitcoin SV network has seen a sudden switch from popular mining pools to individual mining or unknown pools. The last one occurred shortly after TAAL and Coingeek announced they would reduce Bitcoin SV mining fees, seemingly leading many miners to switch mining pools.