Crypto & Trading

Bitcoin’s Security Doesn’t Rely on Block Rewards Alone, Fidelity Argues

By Mag-Info Tech editorial · 2026-06-28

Why the Bitcoin halving cycle sparks security worries

Every four years, Bitcoin undergoes a programmed supply cut known as the halving. Block rewards—the new coins miners receive for validating transactions—are cut in half, reducing the rate at which new bitcoins enter circulation. Critics argue that as rewards shrink, miners may eventually earn too little to justify the cost of securing the network, leaving Bitcoin vulnerable to attacks or centralization. Because the protocol’s security model relies on miners expending real-world resources (electricity, hardware, labor) to produce blocks, any erosion of their profit margins could, in theory, weaken the network’s defenses.

Fidelity Digital Assets pushes back on this narrative in a new research report by analyst Daniel Gray. The paper contends that Bitcoin’s security is not singularly dependent on block rewards. Instead, a combination of factors—including transaction fees paid by users, Bitcoin’s price appreciation over time, and broader market incentives—continue to make mining economically viable even as subsidies decline. The report frames the halving not as a threat to security, but as a natural evolution of Bitcoin’s incentive structure that has repeatedly proven resilient.

How miner revenue has actually grown despite lower rewards

Gray highlights a key empirical point: average daily miner revenue has increased dramatically across halving cycles. During Bitcoin’s first halving cycle, average daily miner revenue was roughly $26,300. Today, that figure exceeds $40.2 million. This rise occurred even though block rewards fell from 50 BTC to 3.125 BTC per block since the April 2024 halving. The explanation lies in Bitcoin’s price appreciation and the growing transaction fee market. When the price of Bitcoin rises, the dollar value of each reward—even a smaller one—grows. Simultaneously, as more users transact on the network, competition for block space drives up transaction fees, adding another revenue stream for miners.

This dynamic suggests that Bitcoin’s security budget—total miner income—does not decline in lockstep with block reward reductions. Instead, it adapts through price and fee markets. Gray’s analysis implies that as long as Bitcoin maintains strong demand and users are willing to pay fees to prioritize transactions, miners will have sufficient incentive to continue securing the network. The report frames the halving as a catalyst that forces efficiency gains and market maturation rather than a structural risk to security.

The role of transaction fees in the post-halving economy

Transaction fees are often cited as the next major revenue source for miners once block rewards eventually reach zero. Fidelity’s report emphasizes that fee markets are already playing a larger role than in earlier cycles. Rising on-chain activity, including ordinal inscriptions and layer-2 rollups, has increased fee pressure, especially during network congestion. Miners now routinely earn millions of dollars per day from fees alone during peak periods. This trend supports the idea that even if block rewards continue to shrink, the fee market can scale to absorb the loss—provided demand for block space remains strong.

Critics counter that fee volatility could make mining income unpredictable, potentially discouraging long-term investment in mining infrastructure. Yet Fidelity argues that the combination of predictable fee growth from sustained adoption and Bitcoin’s long-term price appreciation creates a stabilizing effect. In other words, while fees may fluctuate in the short term, their long-run trajectory is upward if Bitcoin’s utility and value continue to grow. This positions fees not as a stopgap, but as a durable component of the security budget.

Price appreciation as a multiplier for miner incentives

Bitcoin’s price has historically appreciated across halving cycles, often sharply. Fidelity notes that rising prices amplify the dollar value of block rewards and transaction fees alike. For example, a miner earning 6.25 BTC in 2020 saw a much lower dollar value per block than one earning 3.125 BTC in 2024—if the price of Bitcoin doubled or tripled in the interim. Gray’s data shows that miner incentives have historically strengthened alongside price, not weakened. This suggests that Bitcoin’s monetary properties—scarcity and predictable supply—work in tandem with its network effects to sustain miner profitability.

The implication is clear: as long as Bitcoin’s price trajectory remains positive and adoption grows, the economic incentives for miners are likely to remain intact. This challenges the assumption that halving events inherently reduce security. Instead, Fidelity frames them as events that reshape incentives without eroding them, provided the broader macro and adoption trends stay favorable.

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Security depends on total miner income, not rewards alone

Fidelity’s core argument is that network security is a function of total miner income, not block rewards in isolation. The report points out that Bitcoin’s security model is rooted in game theory: attackers would need to amass enough hash rate to reverse transactions or censor blocks, an effort that becomes increasingly expensive as the network grows. Even if block rewards fall, the cost of a 51% attack rises with Bitcoin’s market capitalization and transaction volume. Thus, the economic barrier to attack remains high even as the subsidy component of miner income shrinks.

This reframes the halving debate: it is less about whether miners can cover their operational costs, and more about whether the total cost of attacking the network exceeds the potential reward for an attacker. Fidelity suggests that Bitcoin’s rising price and fee markets increase the opportunity cost of attacking the network, making sustained attacks economically irrational regardless of the block subsidy level.

What could still threaten Bitcoin’s security model

Despite Fidelity’s reassurance, risks remain. One is sustained low Bitcoin prices combined with low on-chain activity, which could compress miner revenue from both block rewards and fees. Another is regulatory crackdowns on mining, especially in regions where energy costs are high or environmental policies tighten. A third is technological disruption—such as a shift to alternative consensus mechanisms or layer-2 solutions that reduce on-chain activity—potentially lowering fee revenue over time.

Fidelity acknowledges these risks but argues they are external to the halving itself. The report implies that as long as Bitcoin retains its monetary properties, strong developer activity, and global demand, the network’s security incentives will remain intact. The focus, then, should be on monitoring broader market and regulatory conditions rather than treating halving events as inherently destabilizing.

Practical implications for investors and users

For investors, Fidelity’s stance reinforces Bitcoin’s long-term investment thesis: scarcity-driven value appreciation and growing utility can sustain miner incentives even as issuance declines. For miners, it suggests that operational efficiency, energy sourcing, and fee market participation will become increasingly important. For developers, it underscores the need to maintain network scalability and fee market health to ensure miners remain economically motivated.

Users should understand that Bitcoin’s security model is robust but not static. While halving events are not a direct threat to security, they do accelerate changes in miner economics. This could lead to shifts in mining geography, hardware preferences, and fee structures. Monitoring miner revenue trends, hash rate distribution, and transaction fee markets can provide early signals about the network’s health.

What to watch next in the halving cycle

The next few years will test Fidelity’s thesis in real time. Key indicators include Bitcoin’s price stability and growth, the evolution of transaction fee markets, and the geographic distribution of hash rate. Observers should also watch for shifts in mining hardware—from energy-intensive ASICs to more efficient designs—and the adoption of layer-2 solutions that could alter on-chain demand. Regulatory developments, especially in major mining hubs, will also play a critical role in shaping miner incentives.

Ultimately, Fidelity’s research suggests that Bitcoin’s security is not a function of block rewards alone, but of a dynamic interplay between price, fees, and network growth. While challenges remain, the historical resilience of miner incentives provides reason for cautious optimism. The halving cycle, rather than undermining security, may be reinforcing it by aligning miner behavior with the network’s long-term value proposition.