So for buying a normal stock in a corporation, when someone buys it, there is generally not a tax consequence until they sell the stock ; other than maybe receiving a dividend. For GBTC, however, even if someone buys and HODL's the shares, there are tax consequences that might need to be reported on the investor's tax return each year, as the trust makes buys/sells. It's treated as if the investor bought/sold Bitcoin directly (based on their percentage ownership in the total trust). I get into a little more in the article below with a link to some resources, the 2017 trust statement wasn't out yet as of when I wrote it:
https://steemit.com/bitcoin/@cryptotax/bitcoin-investment-trust-gbtc-not-as-simple-as-owning-a-stock
Ah yes that does make sense, especially with this new fund coming that states they are going to rebalance every quarter. We desperately need these tax laws changed.