THE first official debt rating to go to a major Hong Kong listed company has been won by Wharf Holdings. Yesterday top United States rating agency Standard & Poors announced that it had awarded the conglomerate a straight ''A'' for its debt. This is likely to be the first of a string of new ratings for local companies. Swire Pacific and Sun Hung Kai Properties are also said to be seeking to have their debt rated. Wharf is also expected to be rated by Moody's, the other leading agency. The S&P stamp of approval on a company opens up the possibilities of tapping the international debt market at advantageous rates, although Wharf director Edward Cheng said yesterday there were no immediate plans to start borrowing money. The instability in the bond market caused by the recent raising of interest rates by the Federal Bank in the US would continue for another month or two, he predicted. However, he added that the rating now offered the chance to consider arranging long-term finance, perhaps for as long as 20 years. ''You can assume that we will be actively seeking opportunities. When conditions are right, we will consider doing some form of fund-raising exercise,'' Mr Cheng said. The Wharf grading will be seen as another step in the build-up of the Hong Kong debt market, which is still tiny compared to the traditional equity business in the territory. A growing number of Hong Kong companies with official ratings will encourage trading of the debt onshore, rather than losing the business to other markets. With Wharf's assets heavily weighted to property, and speculation growing about the future direction of prices, the A rating will be seen as a welcome measure of confidence in the entire sector. Despite the concern that the local market is overheating, S&P has awarded Wharf equal rating with the Hong Kong Government. This is not the highest rating it can award - the rankings are graded down from Triple AAA, through Double AA and A plus - but Mr Cheng said yesterday it was not possible for a corporation to be rated higher than the sovereign debt of the country in which it operates. Analysts say that any debt which has an A rating is regarded as virtually without risk. This reduces the cost of raising funds in the international debt market for the issuer. If Hong Kong's sovereign rating is adjusted because of changing political or economic circumstances, the ratings placed on corporations in the territory would also be adjusted. In November last year Moody's downgraded the debt rating of the MTRC, attributing the move to the increasing influence of China on the territory and probable periods of political uncertainty. Mr Cheng said the granting of a rating would not mean a major shift towards debt financing by the group, which had a policy of keeping its debts at no more than 30 per cent of its assets. The last balance sheet showed a ratio of 12 per cent. Mr Cheng said Wharf could be expected to produce some new, deeper forms of financing in future and the strategy would be to put long-term debts against the longer term projects in which the company was involved.