New York City is getting a surge of new residential buildings with exactly 99 units.

Driven in part by the unintended consequence of a new tax program, developers filed 21 applications for buildings with 99 units in the third quarter, compared to just 13 from 2008 to 2023, according to a report from the Real Estate Board of New York. The trend, experts say, has been fueled by developers seeking to avoid higher worker wages for buildings with 100 or more apartments as part of a new tax incentive.