BRITISH merchant bank Robert Fleming has launched Hongkong's first covered warrant on gold. Fleming, which owns Jardine Fleming equally with Jardine Matheson, is planning to have the issue listed on the stock exchange, where it can be traded like any other listed security. One hundred warrants will entitle the holder to one ounce of .995 fine gold. Each warrant is priced at HK$4.38. The strike price was set at yesterday's London morning fix of US$377.50. This represents a premium of 15 per cent. Robert Fleming said the implied volatility of the issue was 17.5 per cent. The issue expires on June 5, 1995. A spokesman for the merchant bank in Hongkong said last night: ''This has been a popular issue. We have done this type of issue in Europe before. This is the first one we have issued in Hongkong.''