HONG KONG, Feb 14 (Reuters) - Hong Kong's de-facto central bank bought HK$4.223 billion ($538 million) from the market in New York trading hours to stop the local currency weakening and breaking its peg to the U.S. dollar.

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$91.864 billion on Feb 15, an HKMA spokeswoman said on Tuesday.

The latest move to defend the peg came after HKMA bought a total of $30.9 billion equivalent of the local currency from the market in 2022 through 41 rounds of interventions since the U.S. Federal Reserve began hiking interest rates in March last year. ($1 = 7.8499 Hong Kong dollars) (Reporting by Donny Kwok and Georgina Lee; Editing by Leslie Adler)