For the past decade, premium rental property in San Francisco has been aimed at the young: engineers and startup entrepreneurs who have helped the city become a global hub for tech-driven riches.

This, however, might change in the near future. The city's newest luxury housing project, with two-bedroom homes starting at $16,600 a month and going up to $27,000, is intended for wealthy seniors who are old enough to be their grandparents, rather than 30-somethings with IPO fortunes.

Coterie is a senior home development firm formed by two major developers, Related and Atria Senior Living. Its first two offers will be in San Francisco and New York. Coterie Cathedral Hill, a 208-unit apartment project at 1001 Van Ness Ave. in San Francisco, is expected to open in March 2022. A second project, in Manhattan's Hudson Yards, is set to debut in late 2019.

The approach will also appeal to Baby Boomers who grew up in the suburbs, relocated to cities as empty nesters 15 or 20 years ago, and are now in their mid- to late-seventies.