Bitcoin’s 51% Attack Threat: Major Mining Pools Approach 50% Hashrate Threshold

Mining centralization risks push Bitcoin toward its theoretical breaking point.

Hashpower Concentration

Major mining pools now control nearly half the network's total computational power—flirting with the 51% threshold that could theoretically allow transaction reversals and double-spending attacks. That much hashrate in few hands undermines Bitcoin's core decentralized promise.

Market Reactions

Traders shrug while purists sweat. The crypto markets barely flinch—after all, fear sells, but complacency buys lambos. Meanwhile, developers debate protocol changes while mining pool operators swear they'd never attack the golden goose. Sure, just like bankers swore they'd never bundle subprime mortgages.

Security vs. Efficiency

Mining economies of scale create brutal efficiencies—and brutal vulnerabilities. The very competition that secures Bitcoin also drives consolidation toward fewer, bigger players. Who needs Satoshi's vision when you can have profit margins?

The clock ticks toward 51%. Will Bitcoin's guardians intervene—or will the market's invisible hand become a fist?

What Is a 51% Attack?

Proof-of-Work blockchains rely on miners who provide computing power to secure the network. The total computing power is measured as the. A blockchain is considered Immutable because altering its distributed ledger is nearly impossible under normal circumstances.

However, if a single entity or coalition controls, it could manipulate the blockchain. This might allow,effectively undermining the very integrity of the network.

1/ Two Bitcoin pools now control more than 51% of the network hashrate!

That crosses a decentralization red line. A 51% attack becomes technically possible

Why this matters and why ethereum these days looks more decentralized and sustainable than BTC.pic.twitter.com/sAERij4Rnz

— Leon Waidmann(@LeonWaidmann) August 21, 2025

From Theory to Reality

Originally, 51% attacks were largely theoretical, since the. But with the rise of, attackers can now temporarily acquire enough power to launch targeted assaults.

Qubic’s recent campaigns, in which one network attacked another, highlight this evolving landscape. While these attacks typically target, history shows they are not uncommon:

• Expanse (EXP) was attacked in July 2019.
• Litecoin Cash (LCC) suffered six attacks in the same month.
• Vertcoin (VTC) was attacked in December 2019.
• Bitcoin Gold (BTG) endured two attacks in January 2020.

Could Bitcoin Be Next?

Technically, bitcoin has never suffered a 51% attack. The scale of its hashrate makes such a feat. However, history offers warnings: in 2014, the mining pool, before voluntarily reducing its share to ease concerns about centralization.

Today, two mining giants dominate:, together holding. While this doesn’t automatically mean danger, some observers worry about the risk if they were ever to collude.

Experts also note that while private groups lack the resources to sustain such an attack,might, in theory, be able to. Still, the economic incentive remains weak, as controlling Bitcoin temporarily WOULD be enormously costly with little financial upside.

JUST IN:#Bitcoin is now at risk of a 51% attack because two mining pools (Foundry USA and Antpool) control over 51% of the hash power.

Bitcoin today: 2 pools (Foundry + Antpool) >51% → de facto centralization.

Kaspa today: 85% unknown miners (individual)→ de facto… pic.twitter.com/BoptfOkGUy

— 𝐂𝐫𝐲𝐩𝐭𝐨 𝐏𝐫𝐨𝐬𝐞𝐥𝐲𝐭𝐞 (@Crypt0Proselyte) August 20, 2025

Conclusion: Economics Over Fear

For now, Bitcoin remains resilient. While thecannot be fully dismissed, the economic reality aligns with Satoshi Nakamoto’s original conclusions: launching such an attack against Bitcoin is simply

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