Why do CEF and GTU carry such a premium over Net Asset Value?
Because this is the premium people are willing to pay for what they perceive to be 'real bullion' versus 'paper bullion.'
GLD tends to have a negative premium because it is a vehicle for traders, and particularly short sellers.
Deviations from NAV in themselves mean little, if the deviation is steady. It is in the fluctuations that information, and opportunities, are discovered.
"O Jerusalem, Jerusalem. You who murder the prophets, and abuse those whom God has sent as messengers to you. How often I have longed to gather your children together, as a hen gathers her young under her wings. But you would not let me. As you have willed it, so your house is now yours to command— but it is made desolate.”
Matthew 23:37-38