Stablecoins: The Economics of Crypto Pegged to Cash

How stablecoins try to combine cryptocurrency technology with a stable, predictable value.

The earlier lesson on cryptocurrency basics in this module described how volatile many cryptocurrencies can be, with prices swinging sharply over short periods. That volatility makes ordinary cryptocurrencies genuinely impractical for everyday spending or saving - few people want to pay for groceries with money that might be worth 10% less by the time the transaction settles. Stablecoins were built specifically to solve this problem, aiming to combine cryptocurrency’s technology with a stable, predictable value.

What a peg actually means

A stablecoin’s core feature is its peg - a commitment to maintain a fixed value relative to another asset, most commonly the US dollar, so that one unit of the stablecoin is intended to always be worth approximately one dollar. This is a fundamentally different design goal than most cryptocurrencies, which are meant to potentially rise in value as an investment. A stablecoin’s entire purpose is stability itself, making it more useful as a medium of exchange or a way to hold value briefly between other cryptocurrency transactions than as an investment vehicle.

How reserve-backed stablecoins try to keep their promise

What backs a dollar-pegged stablecoin

Imagine a company issues a stablecoin, promising each unit can always be redeemed for one dollar. To make that promise credible, the company holds real dollar-equivalent assets - cash, short-term government bonds, or similar highly liquid holdings - roughly equal in value to every stablecoin unit it has issued. This is called being **reserve-backed**. If someone wants to redeem their stablecoin for actual dollars, the company draws from these reserves to pay them, similar in principle to how a bank holds reserves against deposits, though the specific rules and oversight involved vary considerably between different stablecoin issuers.

Algorithmic stablecoins and why they’re riskier

Not every stablecoin holds real dollar reserves. An algorithmic stablecoin instead tries to maintain its peg through code and market incentives alone - automatically adjusting the coin’s supply, or relying on a connected second cryptocurrency, to push its price back toward the target whenever it drifts away from the peg. This approach avoids needing to hold and manage real reserve assets, but it depends entirely on the underlying mechanism and market confidence continuing to function correctly under stress, with no simple pool of real dollars sitting behind it as a backstop if that confidence breaks down.

Assuming every stablecoin is equally safe simply because it's called "stable"

The word "stablecoin" can create a false sense of uniform safety across very different designs. A well-managed, transparently reserve-backed stablecoin genuinely behaves quite differently from an algorithmic one relying purely on market mechanics to hold its peg. Several algorithmic stablecoins have lost their peg suddenly and dramatically in the past, in some cases collapsing to a small fraction of their intended value within days, precisely because they lacked real reserve assets to fall back on once confidence in the underlying mechanism broke down.

Why stablecoins matter for the broader crypto economy

Stablecoins have become a foundational piece of infrastructure within the cryptocurrency world, often used as a stable resting place for value between trades, or as a way to move funds across borders without necessarily touching the traditional banking system at every step. Their growing size and use have also drawn increasing attention from regulators, who worry that a large, poorly backed stablecoin losing its peg could ripple out and cause broader financial disruption well beyond the cryptocurrency markets it originated in.

Key takeaways

Stablecoins are cryptocurrencies designed to maintain a stable value, usually pegged to the US dollar.
Reserve-backed stablecoins hold real dollar-equivalent assets to support redemptions and maintain the peg.
Algorithmic stablecoins try to maintain their peg through code and market incentives, without holding real reserves.
Algorithmic designs have proven considerably riskier, with some collapsing sharply when confidence broke down.
Stablecoins serve as key infrastructure within crypto markets, used to hold value and move funds between trades.
Their growing scale has drawn increasing regulatory attention over the systemic risk a major peg collapse could cause.