I see this common misconception a ton and Grayscale doesn't seem to want to clear it up, imo this is intentional. GBTC allows what is called an in kind purchase, where you send them BTC and they issue you the amount of shares at the end of the day.
This is not a taxable event and you can sell it on the market (for a premium in the past) after a 6 month period, you have to be an accredited investor though. In the past when the premium was higher than the taxes the seller would incur, they could hypothetically sell the coins and make money or pay less taxes. This arbitrage is what many people are doing to raise their cost averages.
They don't release the numbers of in kind purchases versus USD purchases, but from the last time they did at the end of 2019 it was 80% in kind versus 20% USD. I believe this ratio is more or less the same or only slightly higher as I have asked them multiple times to release the numbers, but they wont.
So when you see headlines like "GBTC buys 700M worth of bitcoin!", realize only 20% of that is probably USD purchased.
[link] [comments]