I have noticed that a Gold ETF and the underlying price of the metal do not necessarily correspond as one might expect.
For example, today 6/24, the price of gold was down approximately $9.00 at the 4pm close of the stock market---yet SPDR gold shares (GLD) closed down only $0.10 despite its $166 price; and in fact, was UP almost the entire time that gold was dropping.
Relatively speaking, I would have expected GLD to be down on the order of $0.84 cents at the close of the market, given that gold metal was down on the order of $9.00 around the close.
QUESTION: What might cause such non-parity behavior on a given day between the price of an ETF and the underlying metal? In fact, as noted, for almost the entire time gold was in negative territory, GLD was in positive territory---an unexpected ``inverse'' performance.