How do co-op and condo owners challenge their assessment in New York City?

Co-ops and condos in New York City are valued and challenged differently from 1-3 family homes, and the deadline is earlier.

They are Tax Class 2. Co-ops, condos, and rental buildings of 4+ units are Tax Class 2, assessed at a 45% level of assessment (see the Determining Your Assessed Value page). The NYC Tax Commission deadline for Class 2 is March 1, two weeks earlier than the Class 1 March 15 date.

Co-ops file as a whole building. A co-op is a single tax lot owned by the cooperative corporation. Individual shareholders do not file their own challenges — the co-op corporation, usually through its managing agent or attorney, files one application with the NYC Tax Commission covering the entire building, and any reduction flows down to shareholders through the maintenance budget. If you own a co-op, ask your board or managing agent whether the building grieves each year.

Condos differ — units are separate lots. Each condominium unit is its own tax lot. An individual condo owner in Tax Class 2 or 4 can file Form TC109, the valuation claim for condominium units, by March 1. Many condo buildings also file collectively through the board.

Valuation method. NYC values Class 2 co-op and condo buildings using an income approach based on comparable rental buildings, not sales of the units. That makes the strongest challenge an argument that the city's comparable-rental selection or capitalization assumptions overstate value — typically handled by the building's professionals.

Bottom line: co-op owners rely on the building's filing; condo owners can file TC109 themselves by March 1 or join the building's collective challenge.