HONG KONG, Dec 16 (Reuters) - Hong Kong's first bitcoin and ether futures exchange traded funds (ETFs) opened flat on their debut on Friday.

The CSOP Bitcoin Futures ETF and The CSOP Ether FUTURES ETF both open at HK$7.77 ($0.99) per unit, compared to their estimated net asset values of HK$7.77 per unit.

Prior to the their debut, the two funds raised a combined $73.6 million from investors. ($1 = 7.7777 Hong Kong dollars) (Reporting by Georgina Lee; Editing by Christian Schmollinger)