Interbank rates yesterday eased from Wednesday's highs after an injection of short-term liquidity by the Hong Kong Monetary Authority and a general perception the turmoil in South Korea would not adversely affect Hong Kong. Traders said lower rates would pave the way for the Hong Kong Association of Banks not to raise deposit rates at today's meeting, implying banks would not need to increase prime rates. The interest rate for one-month interbank lending, with which banks finance most of their assets, came down from Wednesday's 11 per cent to 9.75 per cent, still higher than the existing prime rate of 9.5 per cent. The benchmark three-month interbank lending rate, on which most corporate debts base their interest rates, also eased from 12.5 per cent to 11.875 per cent. Traders said rates opened higher yesterday amid concerns over plunges in the South Korean won and Taiwan dollar, later found to be mostly unfounded. The Hong Kong dollar spot exchange rate weakened marginally in late trade from $7.731 to $7.737 against the US dollar, but strengthened to close at $7.726. The HKMA was believed to have injected short-term liquidity into the market in the morning, lifting the aggregate balance of banks clearing accounts - representing total funds in the market - to $45 billion from $18 billion at the open, traders said.