Fidelity Digital Assets published a detailed rebuttal to claims that Bitcoin's security model weakens after halving events, arguing that hash rate growth, difficulty adjustments and rising transaction fees create a self-reinforcing protective structure.
Bitcoin's network hashrate has surged more than 8,000% since the 2016 halving, Fidelity Digital Assets said in a June 2026 report rebutting claims that the network becomes less secure as block rewards shrink.
"The combination of rising hash rates, automatic difficulty adjustments and growing transaction fee revenue creates a self-reinforcing security model that doesn't collapse when subsidies decline," Fidelity Digital Assets wrote in "Bitcoin's Programmed Security: Part Two," a follow-up to its March 2024 analysis.
The most recent halving occurred in April 2024, cutting block rewards to 3.125 BTC from 6.25 BTC. The next, expected around April 2028, will reduce them further to 1.5625 BTC. During the April 2024 halving, transaction fees in a single block reached approximately 12 times the block subsidy, driven partly by the Runes protocol launch. Fidelity noted that while temporary hash rate dips have occurred after halvings, none resulted in significant security breaches.
The analysis arrives as Bitcoin miners face one of the most challenging periods on record. The network hashrate is hovering near an all-time high of approximately 1 zettahash per second, while Bitcoin trades near $65,000 — down 48% from its October 2025 all-time high of $126,000 — squeezing margins across the industry. BIT (formerly Matrixport) recently described the mining sector as undergoing its most complex restructuring in history, with most companies operating at break-even.
Hash rate growth and difficulty adjustments
Bitcoin's difficulty adjustment mechanism recalibrates every 2,016 blocks, or roughly two weeks, automatically adjusting how hard it is to mine a block. If miners leave the network, difficulty falls, making it cheaper for remaining miners to operate. If miners join, difficulty rises. Fidelity's report found that even in projected low-subsidy environments beyond 2040, the cost of mounting a 51% attack on the network remains disproportionate to any potential gains.
Miners pivot to AI as margins compress
While Fidelity argues Bitcoin's long-term incentive structure remains intact, publicly traded mining companies continue to face near-term financial pressure. Many have diversified into artificial intelligence and high-performance computing, using existing power infrastructure and data center assets. A recent report by VanEck estimated that publicly traded miners could require up to $50 billion in additional capital to fully transition to AI infrastructure, highlighting the scale of the shift.
Blocksbridge Consulting noted in a recent Miner Weekly publication that AI and high-performance computing facilities require higher standards for uptime, cooling, electrical redundancy, networking and customer support compared with Bitcoin mines, which can operate with relatively simple buildings and modular infrastructure.
What comes next
The next halving, currently slated for April 2028, will cut block rewards to 1.5625 BTC, further reducing the subsidy component of miner revenue. Fidelity's analysis suggests that growing transaction fee revenue will increasingly compensate for declining subsidies, though the trajectory depends on continued demand for block space from protocols and applications built on Bitcoin.
This article is for informational purposes only and does not constitute investment advice.
