Grayscale Investments, an Ethereum Investment Trust, sent email responses to select clients who contacted Grayscale over the recent 51% attack on Ethereum Classic ($ETC). According to the email, Grayscale explained that individual investments are safe as 51% attacks are methods of double spending which can not affect other's coins. Grayscale did note that the recent attack threatens the entire cryptocurrency, however. Grayscale has opted out of developed discussion on the attack besides the email to select clients.