Chapter 34: Cryptocurrency

Book: Economics 101

Author: Alfred Mill & Michele Cagan

Type: Chapter

Category: Economics

Difficulty: Beginner

Reading time: 9 min

Core idea

A cryptocurrency is a digital asset whose ownership is recorded on a blockchain — a distributed, append-only ledger maintained by a peer-to-peer network rather than a central authority like a bank or government. Bitcoin (2009) was the first; today over 23,000 cryptocurrencies exist with a combined market value above $1 trillion. The defining technical claim is that transactions can be verified, settled, and made tamper-resistant without trusting a single institution.

Economically, cryptocurrency occupies an unsettled space. It has the name “currency,” but only El Salvador and the Central African Republic accept Bitcoin as legal tender. In most jurisdictions — including the US — it is taxed and regulated as a security or investment property, not money. It can be spent like cash, traded like stock, lost like a forgotten password, or stolen like a wallet. Whether it is “money” depends entirely on which test of money you apply.

Why it matters

It is the first asset class designed without an issuer

Every dollar is a liability of the Federal Reserve. Every Treasury is a promise from the US government. Every stock is a claim on a corporation. A Bitcoin is none of these — there is no issuer, no obligation, no central authority. The price is whatever the next buyer is willing to pay. This is a genuinely novel financial primitive. Whether it turns out to be transformative or a footnote, understanding how it removes the issuer is conceptually important.

Volatility makes it a poor unit of account but an interesting store of value bet

A dollar is worth a dollar tomorrow (modulo inflation). Bitcoin has traded between $3,500 and $65,000 in a single five-year window. That makes pricing groceries in Bitcoin absurd — but it also means anyone willing to bear extraordinary volatility can take a leveraged-feeling bet on adoption without using leverage. The asset’s economic role depends on which property you weight.

It is a new attack surface for fraud

Anonymity, irreversibility, and an opaque regulatory regime are great features if you are a fraud. Rug pulls, fake coins, exchange collapses (FTX), and ransomware payments cluster in crypto for the same reasons whistleblowers and dissidents do. The technology is neutral; the use cases are not.

Key takeaways

Key takeaways

• Cryptocurrency is a digital asset recorded on a blockchain — a distributed ledger that requires no central authority to verify transactions.
• Blockchain records transactions in immutable blocks replicated across many servers; consensus is reached without a trusted intermediary.
• A crypto wallet holds the cryptographic keys (public + private) that authorize transactions. Lose the private key, lose the coins — permanently.
• Custodial wallets are managed by a third party (an exchange); noncustodial wallets put the user in full control and full responsibility.
• Crypto is legal tender in only two countries (El Salvador and the Central African Republic, both for Bitcoin only) — elsewhere it is regulated as an investment.
• Prices swing on supply, demand, social media hype, regulation, and rumor. Bitcoin alone has gone from $3,500 to $65,000 and back to mid-$40,000s within a few years.
• In the US, the IRS treats most crypto transactions — including spending it — as taxable events. Track every transaction or face an audit nightmare.

Mental model — how a blockchain transaction settles

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A peer-to-peer settlement loop with no central clearinghouse.

Read it as: A transaction goes from the user’s wallet, through the network, into a validation step, and — if valid — into a block that is appended to the chain and propagated to every node. There is no bank, no Visa, no central authority deciding. The decentralized validators do collectively what a single trusted institution would do in traditional finance.

Mental model — fiat vs. crypto, side by side

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The same monetary functions, two very different implementations.

Read it as: Money has four jobs — be issued, be backed, be settled, and hold value. Fiat and crypto fill those jobs in radically different ways. Crypto wins on settlement (instant, global, low-fee) and loses on stability and recoverability. Whether the trade is worth it depends entirely on your use case.

Practical application

Setting up a wallet safely

1. Decide custodial vs. noncustodial. Beginner buying small amounts? An exchange custodial wallet (Coinbase, Kraken) is fine. Serious holder? Move to a noncustodial wallet — hardware preferred (Ledger, Trezor).

2. Write down the seed phrase. This is 12 or 24 words. They are the only way to recover the wallet if the device is lost or destroyed. Write them on paper or metal. Store in two separate physical locations. Never photograph, type into a cloud doc, or share with any “support agent.”

3. Test with a small amount. Send a tiny transaction first to confirm everything works. Wallets are unforgiving — a wrong address means the funds are gone.

4. Keep records for taxes. Every receipt, swap, and purchase is potentially taxable in the US. A spreadsheet or a tool like CoinTracker pays for itself the first April you owe.

Tax traps in US crypto

Almost every crypto action is a taxable event

The IRS treats crypto as property. That means:

• Selling crypto for dollars → taxable.
• Trading one crypto for another (BTC → ETH) → taxable.
• Spending crypto to buy goods or services → taxable (you “sold” the crypto for fair market value first).
• Receiving crypto as payment for work → ordinary income at receipt; plus a future capital-gain/loss when you eventually sell.

The only common non-taxable event is buying crypto with US dollars and holding it. Each taxable event requires knowing the cost basis at acquisition and the value at disposal. Track meticulously or budget for a CPA who specializes in crypto.

Example: A freelancer accepts crypto for a small contract

Imagine “Maya,” a US-based illustrator. A startup pays her 0.05 ETH for a logo when ETH is trading at $3,000. Two months later, she swaps the 0.05 ETH for USDC stablecoin when ETH has risen to $3,400.

For US tax purposes, Maya has two taxable events:

1. Income at receipt. The fair market value of the ETH at the moment she received it: 0.05 × $3,000 = $150 of ordinary self-employment income.
2. Capital gain at swap. She “sold” the ETH for $170 (0.05 × $3,400) and “bought” USDC. Her cost basis was $150. So she has a $20 short-term capital gain on top of the original income.

If she then spends the USDC on a $170 software subscription, that is another taxable event — a “sale” of USDC at fair market value. Since USDC is pegged to $1, the gain is negligible, but it still needs to be reported.

So a single $150 freelance gig has generated three reportable transactions before the year is out. None of the dollar amounts are large; the recordkeeping burden is. This is why most casual crypto users underestimate the operational cost of using it for everyday payments — and why fiat money’s invisibility (Maya doesn’t report “spent $5 on coffee”) is itself a feature.

Caveats

Caution

Cryptocurrency is the most volatile mainstream asset class of the past decade and the most fraud-prone. Exchange collapses (Mt. Gox, FTX, Celsius), rug-pull tokens, ransomware demands, and pig-butchering scams have collectively wiped out hundreds of billions of dollars in user funds. The technology is genuinely interesting; the ecosystem around it is dangerous. Never put in more than you can lose, never click “support” links in DMs, and never give your seed phrase to anyone — including someone who appears on a video call claiming to be from your exchange.

Related lessons

Related

Chapter 33: Foreign Exchange and Foreign Trade The traditional currency-trading market that crypto sometimes mimics and sometimes circumvents. Chapter 30: The Money Market The world of short-term traditional debt instruments — useful contrast for the stability tradeoff crypto makes. Concept: Money supply How traditional money is created and constrained — and why fixed-supply cryptocurrencies behave so differently. Concept: Exchange rates The pricing of one currency in another — increasingly relevant as crypto starts to interact with fiat FX markets.