The Hong Kong dollar is pegged to a tight band of between 7.75 and 7.85 versus the U.S. dollar.

The aggregate balance - the key gauge of cash in the banking system - will decrease to HK$120.894 billion on Oct. 6, an HKMA spokeswoman said.

($1 = 7.8499 Hong Kong dollars)

(Reporting by Twinnie Siu and Donny Kwok; Editing by Louise Heavens)