The Four Seasons and the St. Regis hotel projects have some advantage in an economic slump. For one thing they are under construction and protected to some extent from recent investor jitters. In addition, both projects include other uses, namely residential, to help bear the costs.

The 40-story St. Regis, which is being developed by the Starwood hotel chain, will include 100 residential condominiums and penthouses. The 36-story Four Seasons complex, developed by New York City-based Millennium Partners, includes condominiums and retail uses.

Also, with the new west wing of the Moscone Convention Center planned for completion in two years, there is good reason to believe more upscale hotel rooms will be needed. New developments in the next two years could increase the present 34,000 hotel rooms in the city by 10%.