Why has the Grayscale Bitcoin Trust discount hit an all-time high?

Key TakeawaysGrayscale is the largest Bitcoin fund in the world
Discount to underlying asset (Bitcoin) has reached record levels, breaching 50%
Concern about reserves, higher fees and other hurdles explain the discount, which likely won’t close anytime soon 
The discount to net asset value of the Grayscale Bitcoin trust is at all-time highs. The discount briefly pushed past 50%, before pulling back slightly to where it currently sits at 48.8%.  
This comes off the back of the SEC