Bitcoin's total supply crossed 95% of its hard cap earlier this year, with approximately 19.99 million BTC recorded as mined as of January 2026; the figure has continued to climb in the months since. The remaining roughly one million coins will not be fully issued until around 2140, thanks to a design feature called the halving that cuts miner rewards in half every four years. That slow taper is intentional. What it leaves behind, however, is a security model that researchers and miners are still working to solve.

The math behind the cap

Satoshi Nakamoto encoded a ceiling of exactly 21 million BTC into Bitcoin's original protocol. No single party can change it; doing so would require consensus across the entire global network, a scenario considered by most protocol researchers to be highly implausible. Every 210,000 blocks, roughly every four years, the reward paid to miners for processing transactions is cut in half. When Bitcoin launched in 2009, miners earned 50 BTC per block. That figure now stands at 3.125 BTC after the April 2024 halving, producing about 450 new coins per day. The next halving, projected for April 2028, will drop that reward to 1.5625 BTC.

The effective supply ceiling is further complicated by a substantial pool of permanently inaccessible coins. Researchers estimate that between 3 and 4 million BTC have been lost forever due to forgotten private keys, damaged hardware, and inheritance failures. That lost supply will never re-enter circulation, a detail with particular resonance in markets where self-custody is prevalent and inheritance planning around crypto assets remains underdeveloped.

By January 2035, 99% of all bitcoin will have been mined. The remaining 1% will trickle out over the following 105 years, in increments so small that some analysts argue they become economically marginal long before the last coin is produced.

The security budget problem

Currently, miners earn revenue from two sources: the block subsidy (newly issued coins) and transaction fees paid by users. The subsidy dominates. According to a BTC.network block space report from April 2026, fees represented as little as 0.59% of total miner income during low-congestion periods. When the subsidy eventually disappears, fees will be the only revenue left.

"Sustained sub-1% fee contribution ratios, if they persist into future halving cycles, raise legitimate questions about whether fee revenue alone can sustain the hashrate necessary to make 51% attacks prohibitively expensive," the BTC.network report stated. A 51% attack occurs when a single actor controls the majority of the network's computing power, allowing them to reverse transactions or double-spend coins.

New protocols have provided temporary relief. On the April 2024 halving block, one miner collected 37.6 BTC in transaction fees alone, worth roughly $2.4 million, a record at the time, coinciding with the launch of the Runes token protocol on Bitcoin. Bitcoin Ordinals, a system for inscribing data onto individual satoshis (the smallest unit of BTC, at 100 million per coin), generated $46.8 million in sales volume in March 2026. Critics note that these spikes are irregular and fade quickly, leaving fee income volatile between cycles. Some observers describe this dynamic as a "double squeeze": falling subsidies combined with declining protocol activity can compress miner revenue from both directions at once.

What this means for users in Nigeria, India, and Pakistan

The stakes are not abstract for users in high-adoption markets outside the United States. Nigeria has an estimated 22 to 27 million crypto users, with Bitcoin the most commonly held asset among them; approximately 76% of Nigerian crypto investors hold bitcoin, according to data from Breet.io. In India, WazirX and CoinDCX, two of the country's largest exchanges, together report a combined user base of approximately 60 million. Pakistan has seen 18.7% growth in crypto remittance flows via Binance P2P.

In Nigeria and Pakistan, Bitcoin is often used for remittances, everyday payments, and savings rather than speculation. India's crypto landscape is shaped more by regulatory developments, a growing developer ecosystem, and emerging Layer 2 infrastructure than by everyday Bitcoin payments. A fee market that must sustain network security on its own would likely push base-layer transaction costs higher during periods of demand. That is a direct cost to lower-income users sending small amounts across borders.

One widely discussed answer to this problem is the Lightning Network, a payment layer built on top of Bitcoin that processes transactions off-chain. It handles payments at a fraction of the cost, often under $0.01, and processed an estimated $1.17 billion in monthly volume as of November 2025 across more than 17,000 public nodes. The catch is structural: Lightning reduces the number of on-chain transactions, which could reduce the on-chain fee pressure miners will eventually need to rely on. IEEE researchers flagged this tension directly in a 2024 paper examining the protocol's long-term effects on fee markets.

The solution is also not uniformly accessible. In Nigeria, adoption of self-custodied Lightning wallets remains limited due to technical complexity and device constraints. This matters in part because Nigeria's crypto economy is already primarily driven by transaction fees and peer-to-peer volume rather than mining activity. It is also worth noting that approximately 95% of Nigerians prefer receiving payments in stablecoins, meaning a rising on-chain Bitcoin fee market would fall most heavily on the subset of users routing remittances specifically through Bitcoin.

Looking ahead

The 21 million cap itself is not the crisis. The question is whether Bitcoin's fee market will mature fast enough to replace the subsidy as halvings continue to compress miner revenue. Large miners are already diversifying into AI computing and energy infrastructure to stay solvent. Hardware efficiency has improved roughly sevenfold since 2018, falling from around 98 joules per terahash to approximately 13.5 joules per terahash, and miners operating above 25 joules per terahash became unprofitable in most electricity markets after the 2024 halving.

The final bitcoin will not be mined until 2140. But the fee market that must eventually replace the block subsidy will be tested in each halving cycle before then. The next one is less than two years away.