What an ETF is
An ETF is a fund you can buy like a single share, but that holds hundreds or thousands of companies at once. It's the simplest way to spread your money widely.
A basket in one purchase
Picking single companies is hard. An ETF (exchange-traded fund) buys a whole basket for you, for example the 500 biggest US companies (an S&P 500 ETF) or companies across the world. One purchase, many companies.
Index funds
Most popular ETFs simply copy an index, a published list of companies, instead of trying to outguess the market. That keeps their yearly fee (the expense ratio) tiny, often under 0.2%.
Seeing what's inside
Owning a few ETFs can mean owning the same company several times over. Allown's X-ray looks through your funds to show what you really hold.