This ranking orders NYC residential landlords by the total number of open HPD violations across every building in their portfolio, scoped to New York City. Buildings are attributed to a landlord using public corporate filings and ACRIS deed records, which means a portfolio held across many single-purpose LLCs is counted as one owner rather than dozens of unrelated entities.

A portfolio qualifies when it holds at least three graded buildings and carries at least one open violation. Banks, mortgage servicers, trustees, government agencies, and telecom and utility entities are excluded — they hold title without operating the building. Complex ownership structures may be only partially attributed, so counts here are a floor, not a ceiling.

The ranking is re-derived from the city's records several times a day, so it moves as violations open and close. Quote any figure with the snapshot date above; the download carries the same date so a published number stays checkable against it.