At this very moment (about 10:15, 2020/3/24), GLD/IAU are up about 4.5% and PHYS about 3.5%
What causes such differences? Gold bars are in short supply around the world (https://www.ft.com/content/81d915e2-6cef-11ea-89df-41bea055720b) and I saw in the news that the efp between physical gold and futures exploded. But shouldn't that create premium physical gold, such as PHYS, rather than GLD?