ETF creation and redemption helps keep an ETF’s trading price near its net asset value (NAV). Authorized participants exchange a qualifying basket of underlying securities for newly created ETF shares, or return ETF shares to receive the underlying securities. These trades can counter premiums and discounts between market price and NAV. section 4.1.2
A discount arbitrage
Suppose ETF XYZ has $1 billion of NAV and 100 million shares outstanding, so each share represents $10 of underlying assets. If XYZ trades at $9.95, an authorized participant can buy shares, redeem them for a $10 basket of stocks, and capture the apparent $0.05 difference. Buying pressure tends to raise the ETF price and remove the discount. section 4.1.2
Treat the apparent arbitrage as a constrained trading process:
- Include creation or redemption fees, which can range from hundreds to thousands of dollars. section 4.1.3
- Meet provider minimums, often 5,000–50,000 shares or millions of dollars, while accounting for market impact. section 4.1.3
- Model execution delay: adverse price movement can erase the expected profit or create a loss. section 4.1.3
- Expect larger or longer-lived premiums and discounts when holdings are illiquid or trading costs are high. section 4.1.3
The mechanism can also improve tax efficiency. Instead of selling appreciated securities during a rebalance, an ETF can exchange securities with an authorized participant. A heartbeat trade can move replacement holdings into the fund and remove an unwanted holding without a sale, avoiding a realized capital gain in the illustrated case. section 4.2.3
