According to the published data, the Grayscale’s bitcoin trust is responsible for nearly 94% of the firm’s total assets under management
Source: https://cointelegraph.com/news/grayscale-btc-holdings-make-up-197b-of-21b-assets-under-management
Grayscale: BTC Holdings Make Up $1.97B of $2.1B Assets Under Management
May 29, 2019
CoinTelegraph