相对NAV的溢价与折价

ETF 市场价格与净值（NAV）之间的偏差，以及偏差产生的原因。

An ETF trades at a premium when its market price is above its NAV and at a discount when below. The percentage gap is (price − NAV) ÷ NAV. For most large U.S.-equity ETFs the gap stays within a few basis points because authorized participants profit from closing it.

Persistent premiums or discounts appear where arbitrage is harder: funds holding foreign securities (time-zone mismatch), bond funds during stressed markets (stale bond quotes), or funds with capped creations. A discount is not automatically a bargain, and a premium is not proof of quality — both mainly reflect pricing friction.

Practical takeaway: check the typical premium/discount behavior of a fund, and be careful trading in the first and last minutes of the session or when the underlying market is closed.