You do not want to spend all your wages today. Perhaps you are saving for a roof repair several years away. What you need to preserve is not just the account balance, but the ability to pay for that future repair. This role is called Store of Value. A money balance or another asset can fulfil it to varying degrees. What matters is what it will buy later, what holding it costs and whether you can access it. The name is not a promise of risk-free returns.
An undamaged object can sit in your cellar for years after anyone stops wanting it. Durability alone is not enough: when the repair is due, you must be able to sell or use the object on reasonable terms. The Bank of England, the UK’s central bank, describes a store of value in terms of reasonably predictable value over time. This differs from Medium of Exchange, something accepted in payment. A house may retain value for a long time, but you cannot usually pay for groceries with a piece of it. Preserving value therefore concerns future usability, not just physical survival. [1]
A real return measures the change in what your savings can buy — your Purchasing Power. A nominal return tracks the money amount itself. A price index shows changes in the prices of a selected set of goods and services. In our own model, savings rise from 100 000 to 110 000 while a price index rises from 100 to 108. The account shows 10 % more, but shopping has become dearer too. The exact real return is (1.10/1.08 − 1) × 100 ≈ 1.85 %, not exactly 2 %. This compares the growth of savings with that of prices; simple subtraction is only an approximation. The European Central Bank (ECB) explains the difference between nominal and real returns. The US Bureau of Labor Statistics (BLS) notes that its consumer price index (CPI) tracks price changes for an average consumer basket rather than your household’s exact spending. [3] [2]
Return to those savings. Investor.gov, the education website of the US Securities and Exchange Commission (SEC), explains why costs belong in the calculation. From our model’s gross final value of 110 000, subtract a one-off total cost of 4 000, leaving 106 000. Against the starting 100 000, that still looks like growth. With prices up 8 %, however, (1.06/1.08 − 1) × 100 ≈ −1.85 %. The number is higher, but you can buy less. Here we charge the cost at the end; it is neither an annual rate nor a universal tax calculation. The point is why the net result matters. [4]
A price path of 100 → 50 → 75 starts with −50 % and then +50 %. It has not recovered: it remains 25 % below its starting point. Moving from 50 back to 100 requires +100 %, because each percentage uses a different base. Bitcoin.org highlights bitcoin’s price volatility. A long historical chart may look favourable, but that alone neither guarantees recovery nor removes periods when you might have needed to withdraw the money. For savings earmarked for a particular expense, the date of that expense matters too. [7]
Here we compare the US dollar (USD) and the euro (EUR). Investor.gov identifies another layer: changing exchange rates. Our model asset rises from 100 to 110 USD, while the exchange rate moves from 1 to 1.2 USD per EUR. Its starting value is therefore 100 EUR and its final value 110/1.2 ≈ 91.67 EUR. A dollar gain of 10 % simultaneously means a euro loss of about 8.33 % before costs. This is our own model, not a current exchange rate or an actual investment result. Unit of Account is the unit in which prices are expressed. For a planned expense, the unit you will actually have to pay in matters. [5]
A private key is secret data that a wallet uses to create a signature for a payment. Bitcoin.org explains why these keys need protection. With Self-Custody, managing access to your own bitcoin, you must be able to sign a payment or recover access from a backup. If you lose every necessary key and recovery option for 1 BTC (one bitcoin), the chain’s record remains, but you cannot spend the coins yourself. With a service-managed account, withdrawal also depends on the provider’s security and solvency — its ability to meet obligations. Limited issuance restores no keys and guarantees no provider’s promise. Access is part of money’s practical value. [7]
In its explanation of stock quotes, Investor.gov distinguishes bid, the highest price buyers offer, from ask, the lowest price sellers request. Each offer applies to a specified quantity. In our model, the chart shows the last trade at 100. But the available bid for your unit is 98 and the selling fee is 1, leaving net proceeds of 97. A larger sale may exhaust those buy offers and achieve a different price. This is why liquidity matters: how readily you can actually sell the intended quantity. Assess the executable price and net proceeds, not just an indicative screen valuation. [6]
Bitcoin has predetermined issuance rules. That matters, but Bitcoin.org explains price through demand as well as supply. Limited supply alone does not establish how many people will want to buy bitcoin or how many goods it will buy. A claim that Bitcoin functioned as a Store of Value therefore needs a specific start and end date, currency or shopping basket, costs, interim declines and access to the funds. A favourable historical stretch is not a certain future outcome for every holder. A useful explanation presents those conditions alongside the result. [7]
For the clearest picture, read this entry together with Unit of Account, Medium of Exchange, Purchasing Power, Self-custody. The reverse links also lead from Sound money, Monetary Premium, Unit of Account, Medium of Exchange.