Note: the way I use this information is not so much to compare the premiums with each other, although there are some relationships there and significant deviations are of interest. Each of them is different from the others. CEF and GTU are funds holding physical gold and/or silver, and the amounts of metal they hold varies infrequently in well advertised step-wise changes.
GLD and SLV are ETFs, somewhat artificial constructs, in which the amount of metal they hold varies considerably, and intends to track the relationship with spot prices on a somewhat fixed basis.
Rather it serves to compare with data on the premiums of the same fund or ETF over time. One would do this by using the subject category at the bottom of this post, or perhaps doing it for yourself. The premiums expand and contract, excepting GLD and SLV which are control stable, being largely a discount for a management fee. A significant deviation there would be possible evidence of shorting or a paired trade.
