An ETF is one purchase that buys a whole basket.
- A wrapper, not a strategy — always check what is inside
- The expense ratio is charged every year, and it compounds
- It removes single-company risk. Never market risk
What this is about
An ETF — exchange-traded fund — is a fund you buy and sell like a share. One purchase gets you a slice of everything the fund holds. It is the single most useful instrument for somebody who has read You are probably not beating the index and taken it seriously.
It is also the instrument most often misunderstood, because the letters E-T-F say nothing about what is inside.
How it works
A fund holds a basket — say every company in an index. It issues shares in itself, and those shares trade on an exchange all day at whatever price buyers and sellers agree.
Two prices therefore exist at once:
NAV — net asset value, what the underlying holdings are actually worth. Market price — what the ETF's own shares are changing hands at.
They stay close because large institutions can create and redeem ETF shares directly with the fund in exchange for the underlying holdings. If the market price drifts above NAV there is a profit in creating new shares, and doing so pushes it back. This mechanism is why a well-traded ETF tracks its basket closely — and it is worth knowing that it is a mechanism, because it works less well in thin markets and under stress.
What the letters do not tell you
An ETF is a wrapper, not a strategy. "ETF" describes how it trades, not what it holds. Inside the wrapper you will find broad index funds holding thousands of companies, single-sector funds, single-country funds, bond funds, commodity funds, currency-hedged funds, funds that hold other funds, and leveraged products that are not long-term investments at all.
Two things both called ETFs can be as different as a savings account and a casino chip. The letters are not a safety rating.
The three numbers that matter
The expense ratio. The annual cost, taken out of the fund's value continuously. A broad index ETF is typically a small fraction of a percent; niche and active ones can be many times that. It applies every year, on the whole balance, whether the fund rises or falls — which is precisely the kind of small recurring drag that How fees and spread compound shows is not small at all.
What it actually holds. Every ETF publishes its holdings. Read them once. Funds with reassuring names routinely turn out to be concentrated in a handful of companies, and "diversified" is not a regulated promise about how many names there are or how evenly they are weighted.
Tracking difference. How far the fund's return has drifted from the thing it claims to track, after costs. Small and consistent is fine. Large or erratic is a question worth answering before buying.
Physical and synthetic
Most ETFs are physical: they own the actual shares.
Some are synthetic: they own a contract with a bank promising the index's return. This is often cheaper and can track more tightly — and it adds counterparty risk, meaning you now depend on that bank as well as on the market. Collateral arrangements exist to limit this. It is not a scandal, it is a trade-off, and it should be a decision rather than a surprise.
What this does not tell you
It does not tell you an ETF is safe. It removes the risk of one company failing and ruining you. It does not remove market risk. A broad index ETF will fall in a falling market, by roughly as much as the market falls, and no amount of diversification prevents that.
It does not tell you diversification is automatic. A single-sector or single-country ETF can be less diversified than a portfolio of ten hand-picked shares from different industries. The wrapper is not the diversification; the holdings are.
It does not tell you leveraged and inverse ETFs are ordinary ETFs. Products promising two or three times a daily move reset daily, and over longer periods their returns diverge sharply from the multiple people expect — including losing money across a period where the underlying index finished flat. They are short-horizon trading tools. Treating them as long-term holdings is one of the more expensive misunderstandings available to a private investor.
It does not tell you the fund's name is accurate. Names are marketing. Holdings are fact.
Where to see this in the app
Chart works on ETFs exactly as it does on shares — search the ticker like any other. The candles, timeframes and volume all mean the same thing.
Watchlists is the practical place to do the comparison worth doing: put a broad index ETF beside a single sector ETF and beside an individual company, and watch how differently the three behave on a bad day. That is diversification, observed rather than described.
Heatmap shows the market by sector, which is the fastest way to see what a sector ETF is actually exposed to before you buy one.
Portfolio treats ETF positions like any other holding, so a portfolio that is "diversified" through three ETFs that all hold the same large technology companies will show you that concentration rather than hide it.