HONG KONG, July 24 (Reuters) - Hong Kong's Exchange Fund, which is used to back the Hong Kong dollar, posted investment loss of HK$10.6 billion ($1.37 billion) in the first half of 2020, the Hong Kong Monetary Authority (HKMA) said on Friday.

The figure compared with a HK$178.4 billion investment gain in the same period a year earlier.

In 2019, the exchange fund recorded adjusted investment income of HK$262.2 billion.

The HKMA is the key manager of the Exchange Fund, which is controlled by the financial secretary and invests in equities, bonds, foreign exchange and other securities and assets. ($1 = 7.7514 Hong Kong dollars) (Reporting by Twinnie Siu; Editing by Alex Richardson)