Case study · 421-a(16) · Witkoff · 2024–ongoing
The project
The Brook is a 601-foot-tall residential skyscraper at the Fulton–Flatbush intersection in Downtown Brooklyn. Designed by Beyer Blinder Belle, it delivers 591 residential units, of which 178 are designated affordable through 421-a(16) — one of the final wave of projects built under that program before its June 2022 expiration. The tower includes 30,000 square feet of life-enhancing amenities: an outdoor pool, fitness studios, a children’s play area, basketball court, library, and dog run.
The developer, Witkoff, is a global real estate firm headquartered in New York City with over 30 years of experience and projects comprising more than 30 million square feet of development. Witkoff is known for a hands-on, data-driven, and creative approach.
The challenge
The Brook required deliberate, specialized communication with every individual applicant. The ever-changing landscape of subsidized housing programs in New York City — and the sophistication of applicants responding to a Downtown Brooklyn lottery at this price point — meant a one-size-fits-all intake workflow would produce weaker conversion than a conversation-based approach. Improving conversion through better applicant handling was the core objective.
The execution
Regtime’s plan for The Brook leveraged the firm’s deep experience and connections within the affordable housing marketing market. Dedicated team members focused on discrete components of applicant outreach, applicant review, tour coordination, and lease execution. With specialists at each stage of the funnel, the project team operated with concentrated expertise at each handoff point rather than cross-functional generalists.
Advertising launched in April 2025. The campaign strategy anticipated a diverse applicant pool drawn by The Brook’s location at one of Downtown Brooklyn’s most visible intersections — Fulton Mall and Flatbush Avenue.
The outcomes
The Brook’s 178 affordable units are moving through lease-up on schedule, with Regtime’s deliberate applicant-communication model producing the expected conversion profile for a Downtown Brooklyn mixed-income project. The project status as of the time of writing is active marketing, with detailed stats available upon project completion.
What this project established
421-a(16) is not producing new deals, but late-wave projects like The Brook continue to work through marketing and lease-up in 2025 and 2026. The compliance surface of 421-a(16) lease-up — including the market-rate rent stabilization layer that does not apply to 485-x projects — requires practitioners who handled 421-a(16) projects in volume. Marketing teams trained exclusively on 485-x will not be fluent with the threshold-rent architecture that governs 421-a(16) market units.
