HONG KONG, Sept 22 (Reuters) - The Hong Kong Monetary Authority (HKMA) sold HK$2.147 billion ($277.04 million) into the market in New York trading hours after the local currency hit the strong end of its trading band, according to data released by the HKMA.

The aggregate balance - the key gauge of cash in the banking system - will increase by HK$16.872 billion, including HK$14.725 billion sold in Hong Kong trading hours, to HK$241.525 billion on Sept. 23, an HKMA spokesman said early on Tuesday.

The Hong Kong dollar is pegged in a narrow range of 7.75-7.85 to the U.S. dollar. The HKMA has been conducting sales in recent sessions to weaken the currency to keep it within that trading band. ($1 = 7.7498 Hong Kong dollars) (Reporting by Donny Kwok; Editing by Muralikumar Anantharaman)