Bitcoin Passes 20 Million Coins as Supply Cap Debate Returns
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Bitcoin’s 20 millionth coin was mined on 9 March 2026 at block height 939,999, produced by the Foundry USA mining pool, Blockonomi reported. That leaves fewer than one million BTC still to be issued against a cap of about 21 million, or roughly 95.24% of the total supply.
The milestone matters because the remaining coins will not arrive for more than a century. According to the Bitcoin.org halving schedule, the block subsidy falls every four years and is expected to reach zero around 2140. After that, no new Bitcoin will be created through regular mining rewards.
Key facts
- Bitcoin’s maximum supply is about 21 million BTC; about 95.24% had been issued as of March 2026.
- The current block reward is 3.125 BTC, cut from 6.25 BTC at the halving on 20 April 2024.
- Grayscale calculated that total issuance will reach about 20,999,999.9769 BTC, slightly below the 21 million figure usually quoted.
- Cardano caps ADA at 45 billion, Avalanche caps AVAX at 720 million, and XRP created all 100 billion of its coins at launch in 2012.
- The BNB Foundation announced its 37th quarterly burn on 19 October 2026, destroying about 1.65 million BNB and leaving supply near 131.5 million against a 100 million target.
Mining continues, but the revenue mix changes
The supply cap does not switch off the chain. Under Bitcoin’s original white paper, miners were always expected to move from new-coin rewards to fees. Today they earn both the block subsidy and transaction fees; once the subsidy ends, fees become the only direct Bitcoin revenue per block.
Whether that is enough depends on costs and competition. If fees fall too low, some miners could shut down, mining difficulty would adjust, and the remaining operators would produce blocks more easily. Lower total mining power could also reduce the network’s resistance to certain attacks, which is the main long-running concern about the cap.
A 2016 Princeton University paper, On the Instability of Bitcoin Without the Block Reward, studied miners relying only on fees and found incentives that could push them to reorganise recent blocks when fee income varies widely. Blockonomi notes the paper does not prove Bitcoin becomes insecure in 2140; it raises a long-term question rather than an automatic failure.
Other networks take different routes
Cardano’s 45 billion ADA ceiling is written into its constitution. Per Cardano’s documentation on staking rewards and reserves, rewards come from monetary expansion out of finite reserves plus collected transaction fees. As reserves shrink they contribute less, so fees would need to carry more of the burden.
Avalanche mints new AVAX for validators while burning transaction fees, so it may approach its 720 million issuance cap without ever circulating that many coins. Ethereum has no fixed cap at all, offsetting validator issuance with EIP-1559 fee burning; its documentation confirms there is no 120 million ETH ceiling.
XRP shows a third pattern. The XRP Ledger created all 100 billion XRP at launch, and Ripple placed a large share in escrow, so escrow releases can reach the market without raising the total ever created. The ledger also destroys a minimum 0.00001 XRP per transaction, though normal burns are tiny against the 100 billion total.
Why it matters
A fixed cap limits future dilution, but scarcity alone does not set a price. A capped coin still faces falling demand, ownership concentration, token unlock schedules and weak liquidity. Bitcoin’s cap has been public since launch, so it is already priced into how investors view the asset.
What to watch
The next halving is estimated for 2028, when the subsidy would drop to 1.5625 BTC per block. BNB’s next quarterly burn announcement and the pace of fee revenue on Bitcoin will be the data points that test the arguments above. This is not financial advice; cryptocurrency markets are volatile and supply rules can change.
Disclaimer: This article is for information only and is not investment, financial or trading advice. Cryptocurrency prices are highly volatile. Always do your own research.
Source: Blockonomi
