sound money is money whose supply cannot be expanded at will. Savers, workers and businesses can then plan ahead, because the unit keeps its purchasing power better over time.
The problem
Today's money is fiat money: its supply is decided by central banks and created mostly by commercial banks when they lend. That flexibility is deliberate, but it means the value of your savings depends on other people's decisions. Satoshi put it this way in 2009: "The central bank must be trusted not to debase the currency, but the history of fiat currencies is full of breaches of that trust."
Gold: sound, but hard to use
Gold served as sound money for centuries because its supply grows slowly. The World Gold Council estimates about 222,600 tonnes have ever been mined (end-Q2 2026). But gold is heavy, slow to move and hard to verify, so people stored it in banks and used paper claims instead, and those claims could be inflated.
Bitcoin's answer
- Fixed schedule: new coins come only as block rewards, which halve every 210,000 blocks. Total supply ends just under 21 million.
- Verifiable: anyone running a full node can check the total supply themselves.
- Portable: it moves worldwide in minutes, without a vault.
As of October 2026 a little over 20.1 million BTC exist, and the yearly issuance is roughly 164,000 BTC (3.125 BTC × ~52,560 blocks), or about 0.8% of supply (own calculation from block height 972,830).
Takeaway
Bitcoin combines gold's scarcity with digital transport. Its price still swings a lot; "sound" describes the supply rules, not a stable price today.