PARK CITY , Utah — With the developer forced into bankruptcy, Hugh Smith worries about the $1 million he and a partner sunk into bare lots at Promontory, a half-built, sprawling residence club in a post-Olympic town saturated with second homes for wealthy Boomers.

As Promontory began showing signs of distress a few months ago, Francis Najafi , chief executive of Phoenix -based Pivotal Group , gathered members...