Only Authorized Participants can create or redeem ETF shares directly with a fund, trading in blocks the SEC pegs at roughly 50,000 shares and ICI describes as generally 25,000 to 200,000 shares. That in-kind exchange of securities baskets for ETF shares — and its reverse on redemption — is what lets Authorized Participants run the arbitrage that keeps ETF market prices close to end-of-day net asset value.
Who Can Create and Redeem ETF Shares, and What Is the Standard Trade Size?
Only Authorized Participants are permitted to purchase and redeem ETF shares directly from a fund, and they may do so only in large blocks known as Creation UnitsCITE:E1. The U.S. Securities and Exchange Commission's Office of Investor Education and Advocacy gives 50,000 ETF shares as an example of a Creation Unit's sizeCITE:E1. The Investment Company Institute (ICI) describes Creation Units more broadly as generally ranging from 25,000 to 200,000 sharesCITE:E5.
| Source | Entity | Creation Unit size |
|---|
| SEC investor alert | SEC Office of Investor Education and Advocacy | e.g., 50,000 ETF shares |
| ICI viewpoint | Investment Company Institute | Generally 25,000 to 200,000 shares |
How Does In-Kind Creation Work: What Do Authorized Participants Exchange for ETF Shares?
To create new ETF shares, an Authorized Participant assembles and deposits a designated basket of securities and cash with the fund in exchange for ETF sharesCITE:E2. ICI defines this creation basket as a specific list of names and quantities of securities or other assets that may be exchanged for shares of the ETFCITE:E6.
How Does Redemption Reverse the Creation Process?
Redemption runs the creation process in reverse: an Authorized Participant buys a large block of ETF shares on the open market and delivers those shares back to the fundCITE:E3. In return, the Authorized Participant receives a pre-defined basket of individual securities, or the cash equivalentCITE:E3.
How Does the Creation and Redemption Process Enable Arbitrage That Adjusts Market Supply?
The creation and redemption process allows Authorized Participants to engage in an arbitrage strategy that adjusts the supply of ETF shares on the marketCITE:E7. ICI states this arbitrage function is what helps ETFs trade at market prices approximating their underlying valueCITE:E7.
Why Does ETF Market Price Stay Close to Net Asset Value?
An ETF's market price is generally kept close to the ETF's end-of-day NAV per share because of the arbitrage function inherent to the ETF's structureCITE:E4. That alignment traces back to the same creation and redemption mechanism: because Authorized Participants can adjust the supply of ETF shares on the market through this process, ETF prices are able to approximate the value of the underlying holdingsCITE:E7.
What This Means
The evidence traces a single mechanical chain: Creation Units restrict who can transact and at what sizeCITE:E1CITE:E5, in-kind creation baskets define what is exchangedCITE:E2CITE:E6, redemption mirrors that exchange in reverseCITE:E3, and the resulting arbitrage is what the SEC and ICI both point to as the reason ETF market prices stay close to NAVCITE:E4CITE:E7. Each step in this sequence depends on the one before it — remove the Authorized Participant's exclusive access to in-kind creation and redemption, and the arbitrage link connecting market price to NAV as described in this evidence has no mechanism to operate through.
Author's Take・EffectStory 編輯部
What stands out across these mechanics is how narrowly the arbitrage function is gated: only Authorized Participants can transact directly with a fund, and only in blocks as large as the SEC's 50,000-share example or ICI's stated 25,000-to-200,000-share range. That size threshold, combined with the requirement to deposit or receive a specific basket of securities rather than simply cash, means the price-to-NAV discipline described here rests entirely on a small set of participants large enough to assemble those baskets. The indicator worth watching for any given ETF is the composition of its creation basket itself — since ICI defines that basket as the specific list of securities exchangeable for shares, how closely that list tracks the fund's actual holdings is what determines how tightly the arbitrage loop can hold market price to NAV.