Billionaire builder Jorge Perez said a new tax break is making some of his properties even more attractive for development, including a West Palm Beach waterfront parcel he’s had for more than a decade.

The 2017 U.S. tax reform created a path for real estate investors to reduce capital-gains taxes, provided they invest in designated areas in need of jobs and capital, known as opportunity zones. The West Palm Beach site is in one of more than 8,700 such zones across the country, and Perez had already been planning to develop it.

Jorge Perez
Photographer: Eliot J. Schechter/Bloomberg

“It worked as a market-rate rental,” Perez,...