Crypto investment firm Grayscale has refused to share its proof-of-reserves citing "security concerns." The move has stirred up speculations about the financial health of the company. In a Saturday tweet, the company said major cryptocurrency exchange Coinbase, which is used by Grayscale as custodian, frequently performs "on-chain validation," adding that they cannot share their proof of reserves due to security risks. ... Read More: Billion-Dollar Crypto Fund Grayscale Refuses to Post Proof-of-Reserves – Next Firm to Collapse?