Buying an ETF through a brokerage account usually means purchasing shares in the market. It does not normally mean asking the fund to build a small personal basket of its underlying assets. A separate creation and redemption mechanism operates behind that everyday trading.
The U.S. Securities and Exchange Commission’s ETF investor bulletin explains how authorised participants transact directly with covered ETFs in large blocks called creation units. These transactions often involve a basket of securities or other assets, although the specific fund’s arrangements can include cash.
Follow the two routes
In the secondary market, one investor can buy existing ETF shares from another market participant. The transaction changes who owns those shares. It does not by itself prove that the fund issued new shares at that moment.
In a creation transaction, an authorised participant delivers the required assets or cash under the fund’s arrangements and receives a creation unit. Redemption works in the other direction. Investor.gov’s definition of authorised participants describes their contractual relationship with the ETF. They are not simply any investor with a large account.
Use the mechanism to ask better questions
For an illustrative reading exercise, imagine an ETF reports a rise in shares outstanding while trading volume was also high. The two figures describe different activity. Volume counts trading; the change in shares outstanding concerns the amount issued and remaining. Do not treat every traded share as a new share created by the fund.
When reading a fund document, look for who can transact directly, the creation-unit arrangement and whether exchanges are in kind or for cash. Do not assume that an example unit size applies to every ETF or that every exchange-traded product has the same legal structure.
The creation and redemption process helps explain ETF market structure, but it does not remove investment risk or guarantee that a market price always equals asset value. Understanding the route by which shares enter and leave the fund is one part of reading the product, not a recommendation to buy it.