I'll stick to GLD in my comment. I don't believe what you said is correct, so I agree with orogozoru. They don't sell "Units of the trust." They sell some of the gold held in the case of GLD. They then tell you to adjust your share cost basis according to the results of those sales, and tell you to determine whether you have a capital gain or loss as explained here: https://ttlc.intuit.com/community/retirement/discussion/re-what-is-the-proper-way-to-adjust-the-cost...
BTW, they use the term "unit" interchangeably with "share" in their prospectus, but the rules on tracking sales for fees differ from non-trust ETFs like SPY etc.
That has to reduce the NAV by the amount of the proceeds. Anyone buying the exact same shares from me the next day would be buying shares representing less gold, and the cash goes into the manager's pocket, so the NAV must be lowered by the manager. That means that when the investor lowers his/her cost basis, the NAV is falling too, so it washes out except for the capital gain/loss on the sale of gold from the trust. If they take $10 of gold out of your shares to pay their fees, they must also reduce the NAV of the trust by that same amount of gold.
This is essentially a double hit to the investor, which in a "normal ETF" (non-trust) would simply be deducted from the gains. Seems ridiculous to penalize investors that way.
That also means orogozoru who questioned you previously has to do these calculations to lower his cost basis in GLD etc. which will increase the gain and the resulting tax when sold. The IRS does not appreciate "guesses" unless you overpay your tax. But the way to simplify it for orogozoru and others would be to 1. Take the entire sale total for the year (add up all the months) as a capital gain and pay extra tax. and 2. Subtract the entire sale amount, not adjusted for the cost basis, from the prior year's ending cost basis. That would maximize the tax owed both on any capital gain if there was one and maximize taxes at the time of sale of GLD shares, but would reduce the effort. Take your pick! I prefer to pay the tax owed, but to each his/her own. 😉
