Cryptocurrency: What You Own and How to Size It

Cryptocurrency is the investment people argue about most and understand least. Supporters see a new kind of money and financial system; critics see speculation with no underlying value. You do not need to settle that argument to make a sound decision. You need to know what you would own, how it can be lost, how it is taxed, and how big a position you could hold without one bad year undoing your plan. This chapter covers those four things, in that order.

What a cryptocurrency is

A cryptocurrency is a digital asset whose ownership is recorded on a blockchain: a shared ledger copied across thousands of computers. Transactions are grouped into blocks, and each block is linked to the one before it with cryptography, so changing an old record would mean redoing every later block across most of the network. No bank or government keeps the ledger; the network's rules and the agreement of its participants do.

Ownership rests on a pair of keys. A public key works like an account address that anyone can send to. A private key is a secret number that authorises spending. Whoever holds the private key controls the coins. There is no password reset, no customer service line, and no way to reverse a transaction once the network confirms it.

The main kinds you will meet:

• Bitcoin was the first, launched in 2009. Its rules cap the total supply at 21 million coins. Supporters treat it as a scarce digital store of value, a kind of digital gold.
• Ethereum is a platform for programs that run on its blockchain, called smart contracts, used for lending, trading and other applications without a central company. Its token, ether, pays for running those programs. It has no fixed supply cap.
• Stablecoins are tokens designed to hold a steady value, usually one US dollar, backed by reserves such as cash and Treasury bills. They are used for trading and payments rather than as investments. A 2025 federal law set rules for issuers of payment stablecoins, including reserve requirements.
• Thousands of other tokens exist. Many have failed, and many are thinly traded and easy to manipulate.

The case for, and the case against

The case for. Bitcoin's fixed supply makes it scarce by design. The networks run without a central operator and allow anyone with an internet connection to send value across borders. Regulated access has widened: exchange-traded products that hold bitcoin directly have traded in the US since 2024, and ether products since later that year. Some investors see a small holding as an option on a technology that could become much more widely used.

The case against. Cryptocurrencies produce no earnings, interest or rent, so there is no cash flow from which to estimate a fair value; the price is whatever buyers will pay. Prices are extremely volatile, and bitcoin has fallen more than 70% from a peak more than once. The industry has seen large fraud and failures, including exchanges that collapsed with customer money. Regulation is still changing. And a large share of tokens have lost nearly all their value.

Both cases can be true at once. That combination, a possible large gain and a real chance of large loss, is the reason the size of any position matters more than the choice of coin.

How to size a position you can live with

Start with what a severe fall would do to your plan, not with how much the price might rise.

A position of $5,000 that falls 75% in a year, a decline bitcoin has matched or exceeded from its peaks more than once, is worth about $1,250. Whether that is tolerable depends entirely on what share of your savings it was, and whether you would sell in a panic at the bottom.

A common framework among investors who hold cryptocurrency at all:

• Foundations first. A full emergency fund, no high-interest debt, and retirement saving on track before any speculative holding.
• A small share of investable assets, often described as 1% to 5%, and many investors choose none. The idea is that a total loss would hurt but not change your retirement date or your housing.
• Only money you will not need for years, because the price can stay far below what you paid for a long time.
• A fixed target, rebalanced like any other holding. If the position surges to many times its target, trimming it back locks in part of the gain and keeps one asset from dominating your risk. The asset allocation calculator and rebalancing calculator handle this the same way as for stocks and bonds.
• Steady buying rather than a single large purchase reduces the chance of buying everything at a peak. The lump sum versus dollar-cost averaging calculator shows the trade-off.

Keeping it safe: custody and scams

How you hold cryptocurrency decides who can lose it.

At an exchange or broker (custodial). The platform holds the private keys for you. It is convenient and you can recover a forgotten password. The risk is the platform: if it is hacked, freezes withdrawals or fails, your coins are at stake. Cryptocurrency held at a platform is generally not protected by FDIC deposit insurance, and SIPC protection, which covers up to $500,000 of securities and cash when a member brokerage fails, generally does not cover digital assets that are not securities. Check the platform's own terms.

In an exchange-traded product. You own shares in a fund that holds the coins through a regulated custodian, inside an ordinary brokerage or retirement account. You give up direct control and pay a yearly expense ratio, but there are no keys to lose.

In your own wallet (self-custody). You hold the private key, often on a hardware wallet kept offline. No company can freeze or lose your coins, but nobody can recover them either. Lose the device and the backup recovery phrase, and the coins are gone permanently.

Whatever you choose:

1. Never share a private key or recovery phrase with anyone, including someone claiming to be support staff. No legitimate company asks for it.
2. Store the recovery phrase offline, in more than one secure place, and never as a photo or a cloud note.
3. Turn on app-based two-factor authentication at every platform; avoid text-message codes, which can be hijacked.
4. Treat any offer of guaranteed returns, any unsolicited investment advice from a new online contact, and any request to move coins to "secure" them as a likely scam.
5. Test a new address with a small transfer first; transactions cannot be reversed.

How cryptocurrency is taxed

The IRS treats cryptocurrency as property, not currency. That means:

Taxable events: selling for dollars; trading one cryptocurrency for another; spending it on goods or services; and receiving it as pay, mining or staking rewards (taxed as ordinary income at its value when you gain control of it, which then becomes your cost basis).

Not taxable: buying with dollars and holding; moving coins between wallets you own; and giving a gift within the annual gift exclusion (the recipient takes your cost basis).

Gains on coins held one year or less are short-term and taxed as ordinary income; gains on coins held more than a year are long-term and taxed at 0%, 15% or 20%, with the 0% rate applying while taxable income stays at or below $49,450 single or $98,900 joint in 2026.

A single filer with $80,000 of income owes about $8,770 in federal income tax in 2026. Selling coins held for less than a year at a gain that lifts income to $90,000 raises the tax to about $10,970, because short-term gains are taxed at the 22.0% bracket rate. Had the same coins been held more than a year, this filer's taxable income is already above the 0% band, so the gain would have been taxed at the 15% long-term rate instead: a smaller bill from nothing more than waiting.

Losses offset gains, and up to $3,000 of net loss a year can be deducted against other income. Under current rules the wash sale rule (chapter 1) is written for stock and securities, and the IRS has not applied it to cryptocurrency held directly, though Congress has considered changing that; check the current year's instructions before relying on it. Cryptocurrency held through an exchange-traded product is a security, so the wash sale rule does apply to it.

Reporting has tightened. Form 1040 asks every filer whether they received, sold or exchanged digital assets. Brokers file a new Form 1099-DA reporting sales, starting with gross proceeds for 2025 transactions and adding cost basis for assets acquired from 2026 onward. Keep your own records of every purchase date and price; if you move coins between platforms, the receiving platform may not know your basis.