BACK in mid-October when the Hang Seng Index had just broken through 8,000 points, Henderson Land stunned investors by announcing a revaluation of its property portfolio to $42.69 a share - 94 per cent more than its accepted valuation of $22. While analysts remained sceptical of the exercise, investors enthusiastically responded by pumping up Henderson's stock price by $4.50 - 18.59 per cent - to $28.70 the day after the announcement. Since the revaluation, Henderson has soared 143.8 per cent to $59 while the Hang Seng Index has climbed 47.5 per cent. In the process, Henderson became Hong Kong's best performing Hang Seng constituent last year. Given this scenario, it would not be surprising to see Sino Land's price jump sharply today after announcing last night a revaluation of its property assets outside China and listed investments to $32.02 billion, or $16.32 a share. This is 26.5 per cent more than Sino Land's market capitalisation of $25.3 billion and more than double its consolidated net tangible asset value of $15.29 billion as of June 30, 1993. It is important to point out that as Henderson Land jumped 143.8 per cent, Sino Land moved ahead 113.2 per cent during the same period. This is a strong indication that the excitement surrounding Henderson Land's revaluation was transferred to other property counters. Through the same period, Cheung Kong (Holdings) has climbed 69.8 per cent, Hutchison Whampoa 57.2 per cent, Sun Hung Kai Properties 90.2 per cent and New World Development 89.5 per cent. As a result, it is not be out of line to suggest that Sino Land has already enjoyed a strong run and further gains may not be possible. However, there are two reasons to suggest that Sino Land will probably follow in Henderson Land's footsteps: one, Hong Kong's marathon-like market, and two, Sino Land chairman Robert Ng, who is gradually establishing a strong following in the wake of hisstunning $3.94 billion bid on behalf of a consortium last month for a site in Kowloon.