24 C.F.R. § 891.215

(a) HUD may establish, through publication of a notice in the Federal Register, limits on the number of units that can be applied for by a Sponsor or Co-sponsor in a single geographical region and/or nationwide.

(b) Affiliated entities that submit separate applications shall be deemed to be a single entity for purposes of these limits.

(c) HUD may also establish, through publication of a notice in the Federal Register, the minimum size of a single project.