GBTC premium is the market price divided by holdings per share: https://grayscale.co/bitcoin-investment-trust/#market-performance
lol lil bit. And a good indicator that all you longs should take profits and chill for a bit. I am the master of buying the top.
I believe my answer may have been correct when GBTC first came out but it is now in error. You now have to multiply the current BTC price by the 655,540 coins that GBTC owns and then divide that total by the 692,370,100 shares of GBTC outstanding. That will then give you the Net Asset Value per share. You then compare the NAV with the GBTC trading price to determine the premium or discount. Sorry for giving you some incorrect information. I have been bothered by the fact that GBTC was at a substantial apparent discount per my prior method and I intuitively knew that could not be correct so I did some research that unearthed my error. And, after I posted this I discovered that @markd01 in post #31 posted the Grayscale site that does all this calculation for you. Thanks, Mark