Figures computed from the FY2026–27 DOF assessment roll. Surcharge estimated at the flat Phase-1 rates (4% $1–3M, 5.25% $3–5M, 6.5% over $5M) on each unit's full DOF market value; applies to non-primary residences only.
The quantitative picture
DOF market values at 520 Park Avenue run from about $351,000 at the low end to $10,227,653 at the top, with a median of $5,101,894 — meaning the typical unit already clears the $1M threshold. A median unit that isn't a primary residence owes roughly $331,623 a year (6.5% of its full DOF value); the building's most valuable residence owes about $664,797 a year at the 6.5% rate. Across the 36 exposed units, the surcharge totals an estimated $13.1 million annually — an average of about $364,740 per exposed unit.
Of those 36 exposed units, 1 carry DOF values between $1M and $3M (the 4% band), 2 between $3M and $5M (5.25%), and 33 above $5M (6.5%) — most of the exposed units sit in the 5.25%–6.5% bands, where the flat rate bites hardest.
The last three closed sales
From ACRIS, the building's three most recent recorded deeds over $1 million:
| Date | Residence | Recorded price |
|---|---|---|
| Mar 19, 2026 | 18 | $11,600,000 |
| Jul 29, 2025 | 31 | $22,000,000 |
| Nov 20, 2024 | DPH63 | $78,964,000 |
Note the gap between these prices and the tax base: the surcharge is charged on the DOF market value — an income-derived figure that runs far below open-market numbers — not on what a unit trades for. A residence that closes at $11.6M does not owe 6.5% of $11.6M; it owes the flat rate on its (much lower) DOF market value. That distinction is the single most misunderstood part of the tax, and the reason a free DOF-value lookup is worth more than any sale-price estimate.
The building
520 Park Avenue was completed in 2018 and was designed by Robert A.M. Stern Architects. It was developed by Zeckendorf Development, and it is a 54-story limestone condominium tower on the Upper East Side.
Where it is
520 Park Avenue, Upper East Side.
Is your 520 Park Avenue unit exposed?
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Check My Unit — FreeDisclaimer & method. Educational information from Conquest, a licensed New York real estate brokerage — not legal, tax, or accounting advice. Building figures are computed from the FY2026–27 DOF assessment roll at the statutory flat Phase-1 rates (4% $1–3M, 5.25% $3–5M, 6.5% over $5M) on each unit's full DOF market value, and represent exposure if every over-threshold unit were a non-primary residence; actual liability depends on each owner's occupancy and exemptions. Sale prices are recorded deeds from ACRIS.