GBTC is currently trading at a 24.89% discount to its NAV. If the conversion to an ETF is likely, based on a recent lawsuit win, the discount is expected to tighten.
Discussion
That's yesterday's discount. It went up 17% while BTC went up 5%, so the discount shrunk quite a bit today.
18.06 according to this. https://ycharts.com/companies/GBTC/discount_or_premium_to_nav