521 Park Avenue
521 Park Avenue, New York, NY 10065
BBL 1013957502 · BIN 1041910
- Year built
- 1911
- Type
- Condominium
- Units
- About 24
- Floors
- 12
- Landmark status
- Not an individual landmark; not in a historic district
- NYC Landmarks Preservation Commission and City Planning records, updated February 2026
- Leasing by owners
- Permitted
- Pets
- Pets permitted; species and limits not stated
- Doorman
- Full-time doorman
Every recorded sale at this building, 2003–2026
Price-per-square-foot over time, the line- and floor-premium curves, and every recorded sale.
- Median $/sf, 2026 to date
- $1,297
- floor-adjusted, 3 sales
- Listing discount
- 5.9%
- Recorded sales
- 29
- On record
- 2003–2026
Own an apartment here? See what it would sell for.
A Private Pricing Opinion — what your apartment at 521 Park Avenue would likely sell for today, what it costs to sell, and what you’d walk away with — reviewed personally against condition, exposures, renovation quality, and the competition actually on the market.
521 Park Avenue is a rare thing: a pre-WWI Park Avenue luxury apartment house — and one of the earliest, dating to 1911 — that today offers condominium ownership rather than the cooperative structure that governs almost every building of its vintage. Designed by William A. Boring and built at the northeast corner of Park Avenue and East 61st Street, the building was erected as a cooperative at a moment when Park Avenue itself was still being transformed from an open railroad cut into the residential boulevard it would become. In 1987 it was converted to a condominium, and it operates today as a boutique building of roughly two dozen residences.
That history produces an unusual proposition. Buyers get the architecture of an early Park Avenue prewar — full-floor planning in the original conception, the proportions and ceiling heights of the era, a dignified corner address with exact LPC jurisdiction to confirm for the tax lot — paired with condominium ownership (the apartments are deeded condominium units, DOF class R4): leasing by owners is permitted, and financing, pied-à-terre and investment use and the purchase process should be confirmed in the current governing documents. On Park Avenue, that combination is distinctive.
The building's intimate scale reinforces the appeal. Originally designed around full-floor apartments, the building has seen reconfigurations over the decades that produced its current roster of around 24 residences. The result is a prewar building with varied configurations at one of Lenox Hill's most desirable corners.
Architecture and unit composition
521 Park Avenue is a 12-story pre-WWI luxury apartment house in the restrained classical idiom of the early Park Avenue tradition. Its original conception centered on full-floor apartments — the most generous planning of the era — and although decades of combinations and modifications have changed the original apartment count, the building retains the bones and proportions of an early Park Avenue prewar.
The residences carry the era's signatures where preserved: gracious room proportions, high ceilings, and the formal layouts that defined pre-WWI luxury. Corner exposures at Park and 61st bring strong light. As with any building of this vintage and small scale, configuration, floor, and renovation history drive substantial apartment-to-apartment variation.
Building operations
521 Park Avenue operates as a boutique full-service condominium: a full-time doorman, a live-in superintendent, and private storage, on a scale calibrated to roughly two dozen residences. Assess apartment and common-area noise directly and compare actual charges and reserve obligations; residence count does not establish either.
The building is a condominium (the apartments are deeded condominium units, DOF class R4); confirm financing, pied-à-terre and leasing rules in the current declaration, bylaws and house rules. Leasing by owners is permitted, and pets are permitted; species and limits are not stated. Any building-specific financial particulars (assessment history, reserve posture) are worth reviewing at offer stage.
Application and transaction fees
Fees below are from building management's published schedule, as of September 2026. They are shown as published, item by item; no total is added because the total depends on the transaction. Deposits are listed apart from nonrefundable charges.
Purchase
8 items
Fees and charges
| Item | Paid by | When | Amount | Refundable |
|---|---|---|---|---|
| Application Processing FeePaid to management | Paid by Buyer | When With the application | Amount $750 | Refundable Non-refundable |
| Credit/Background Check FeePer applicantPaid to management | Paid by Buyer | When With the application | Amount $150 per applicant | Refundable Non-refundable |
| Move-In FeePaid to the building | Paid by Buyer | When With the application | Amount $5,000 | Refundable Non-refundable |
| Working Capital ContributionPaid to the building | Paid by Buyer | When With the application | Amount Equal to one month's common charges | Refundable Non-refundable |
| Move-Out FeePaid to the building | Paid by Seller | When With the application | Amount $5,000 | Refundable Non-refundable |
Deposits
| Item | Paid by | When | Amount | Refundable |
|---|---|---|---|---|
| Move-In DepositPaid to the building | Paid by Buyer | When With the application | Amount $5,000 | Refundable Refundable |
| Move-Out DepositPaid to the building | Paid by Seller | When With the application | Amount $5,000 | Refundable Refundable |
| Post-Closing Document DepositPaid to the building | Paid by Buyer | When Upon approval | Amount $500 | Refundable Refundable |
Rental or lease
8 items
Fees and charges
| Item | Paid by | When | Amount | Refundable |
|---|---|---|---|---|
| Move-Out FeePaid to the building | Paid by Landlord | When With the application | Amount $5,000 | Refundable Non-refundable |
| Application Processing FeePaid to management | Paid by Tenant | When With the application | Amount $575 | Refundable Non-refundable |
| Credit/Background Check FeePer applicantPaid to management | Paid by Tenant | When With the application | Amount $150 per applicant | Refundable Non-refundable |
| Lease FeePaid to the building | Paid by Tenant | When With the application | Amount Equal to one month's common charges | Refundable Non-refundable |
| Move-In FeePaid to the building | Paid by Tenant | When With the application | Amount $5,000 | Refundable Non-refundable |
Deposits
| Item | Paid by | When | Amount | Refundable |
|---|---|---|---|---|
| Move-Out DepositPaid to the building | Paid by Landlord | When With the application | Amount $5,000 | Refundable Refundable |
| Move-In DepositPaid to the building | Paid by Tenant | When With the application | Amount $5,000 | Refundable Refundable |
Lease renewal
Fees and charges
| Item | Paid by | When | Amount | Refundable |
|---|---|---|---|---|
| Application Processing FeePaid to management | Paid by Tenant | When With the application | Amount $225 | Refundable Non-refundable |
Management updates its schedule without a public filing. The date is when management last updated the page, not when a rule changed. Confirm the current schedule with management before you apply.
Considering an apartment here? Send Corey the listing to discuss the building's costs and purchase requirements.
Own an apartment here? Request an apartment-specific pricing review.
Financing and purchase requirements
- Guarantors
- PermittedSource: building management's published schedule, as of September 2026
Sublet and pied-à-terre policy
A condominium owner leasing a unit and a co-op shareholder subletting are different rules, and a building-wide rule is different from a restriction on one apartment. This is the building's rule; confirm it for the specific apartment.
- Leasing by owners
- PermittedSource: building management's published schedule, as of September 2026
- Short-term rentals
- Not permittedSource: building management's published schedule, as of September 2026
- Pied-à-terre ownership
- Not verified
Considering an apartment here? Send Corey the listing to discuss the sublet and pied-à-terre rules for that apartment.
Pets and in-unit washer/dryer
- Pets
- Pets permitted; species and limits not statedSource: building management's published schedule, as of September 2026
- In-unit washer/dryer
- Not verified
Considering an apartment here? Send Corey the listing to confirm the pet and washer/dryer rules for that apartment.
Monthly carrying charges in recent sales
- Common charges + taxes, per room
- $1,820 per room a monthMedian of 4 recorded sales since October 2023Source: recorded sales, refreshed October 2026
- Common charges + taxes, per square foot
- $4.09 per square foot a monthMedian of 5 recorded sales since October 2023Source: recorded sales, refreshed October 2026
- Common charges alone, per square foot
- $2.24 per square foot a monthMedian of 3 listings since October 2023 that give the annual taxSource: listing records, refreshed October 2026
- Real estate taxes alone, per square foot
- $1.18 per square foot a monthMedian of 3 listings since October 2023 that give the annual taxSource: listing records, refreshed October 2026
Common charges plus real estate taxes, combined into one monthly figure the way New York condominium listings show them. Add a mortgage payment for the monthly outlay. The split into common charges and taxes comes from the listings that also give the annual tax, a different sample, so the two lines need not add up exactly to the combined median; a tax abatement can hold taxes below the full amount until it expires. A summary of recorded sales and listings, not a current bill; charges change.
Building staffing and amenities
- Doorman
- Full-time doormanSource: The Roebling Team's building profile
- Live-in superintendent
- YesSource: The Roebling Team's building profile
- Elevator
- YesSource: NYC Department of Buildings elevator records
- Amenities noted
- StorageSource: The Roebling Team's building profile
Staffing and amenities as our building profile and recent listing records describe them. A feature not listed is not confirmed absent. Outdoor space, parking and some facilities can belong to particular apartments or to a separate owner; confirm access for the specific apartment.
Local Law 97
- 2024–2029 annual penalty
- $20,775/yr
- 2030–2034 annual penalty
- $69,990/yr
- Per unit / month range
- $72 – $243
- Modeled exposure split equally across 24 units (the residential count on the city's lot record). Not an assessed amount; condominium owners are typically charged by each unit's common-interest percentage.
Source: NYC LL84 benchmarking and PLUTO · The Roebling Research Library. City data last refreshed October 2026.
See full Local Law 97 analysis — emissions history, scenarios, methodology →Facade safety — Local Law 11
The latest available FISP filing classified the facade as Safe — no repairs were required at that inspection. A filed Safe grade is not a guarantee of current condition: owners still maintain the facade and, where required, observe parapets each year. Future inspection timing (Local Law 49 of 2025 changed the cycle framework from October 1, 2026), repair and any assessment decisions remain building-specific.
How to read this, and where it comes from
QEWI = Qualified Exterior Wall Inspector — a licensed professional engineer or registered architect who meets DOB’s FISP qualifications and signs the report (the independent expert, not the managing agent).
Source: NYC DOB facade filings (FISP) · The Roebling Research Library. City data last refreshed October 2026.
Management & transfer contacts
- Sublet policy
- Allowed
- Policies and fees
- Working Capital Contribution = one month's common charges; Move-in/out deposits & fees $5,000 each; App Processing $750. No flip tax listed
Photographs of 521 Park Avenue
Recent sales
Recent closings at this building, from The Roebling Research Library. Prices are the transfer amounts recorded with the NYC Department of Finance; apartment-level detail is checked against the building’s own file in The Roebling Research Library before publishing.
| Date | Unit | Apartment | Price | PPSF | vs. Ask |
|---|---|---|---|---|---|
| Sep 17, 2026 | 10A | 1 BR · 1.5 BA · 1,000 sf | $1,550,000 | $1,550/sf | -13.9% |
| Sep 3, 2026 | 11A | 1 BR · 1.5 BA · 1,058 sf | $1,700,000 | $1,607/sf | — |
| Aug 21, 2026 | 10C | 2 BR · 2 BA · 1,683 sf | $2,400,000 | $1,426/sf | -12.7% |
| Aug 25, 2025 | 11B | 3 BR · 2 BA · 1,468 sf | $2,200,000 | $1,499/sf | -24.0% |
| Dec 5, 2024 | 2A | 1 BR · 1.5 BA · 1,911 sf | $2,000,000 | $1,047/sf | -32.2% |
| Apr 19, 2024 | 5BC | 4 BR · 4.5 BA · 3,440 sf | $4,625,000 | $1,344/sf | -22.3% |
| Aug 19, 2021 | PH11C | 3 BR · 5.5 BA · 3,040 sf | $7,450,000 | $2,451/sf | +0.0% |
| Jul 8, 2021 | 12A | 2 BR · 2 BA · 909 sf | $1,995,000 | $2,195/sf | +0.0% |
Market read. Most recent trades (2026 to date) cleared a median $1,297/sf (floor-adjusted) across 3 sales. Floor-adjusted means each sale is restated to a constant mix of floors, so the figure can differ from the plain median of the sales listed above. Median listing discount 5.9% from the last ask — a recurring negotiation gap worth pricing into any offer or listing strategy.
The retrade record
Lines that have traded more than once in the public record — the building’s appreciation arc, apartment by apartment.
Full closing history with price-per-square-foot over time, the complete retrade record, and every line that has traded.
Sales sourced from NYC Department of Finance recorded transfers (BBL 1-01395-7502; each condominium apartment is its own tax lot). Apartment-level facts (line, condition, asking-price context) curated and cross-verified in The Roebling Research Library. Not all transactions cross-verify with ACRIS records — sponsor and LLC purchases sometimes record at stipulated values rather than market price; square footage from recorded condo declarations and offering plans.
What would your apartment rent for?
Enter your apartment and I'll send you what it would rent for, from comparable closed leases at 521 Park Avenue and nearby.
At the recent median sale of $2M (5 sales in the past 24 months, since November 3, 2024), a buyer putting 25% down would pay about $85,625 to close, or 4.3% of the price.
- Mansion tax: $25,000
- Mortgage recording tax: $28,875
- Title insurance: $9,000
- Attorneys, lender, building fees, reserves and filings: $22,750
Assumes a resale (the seller pays transfer taxes), a $4,500 attorney fee and a mortgage on the rest.
Keep up with 521 Park Avenue and its market
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What to know if you’re buying
You are buying an early Park Avenue prewar with condominium flexibility. That pairing — pre-WWI architecture and condominium ownership on Park Avenue — is rare and is the building's core value.
The condominium structure is the differentiator. There is no co-op board admission, and leasing by owners is permitted; confirm financing, pied-à-terre and ownership-entity rules in the current declaration, bylaws and house rules.
Check the available comparable sales. The building has around 24 residences; assess actual turnover and matched sales before selecting apartment-level pricing.
Pets are permitted under the condominium rules.
Confirm current financial particulars at offer stage. Common charges, any active assessment, and reserve posture should be reviewed in the offering plan and financials during contract review.
What to know if you’re selling
Lead with the prewar pedigree and the condominium structure. An early Park Avenue luxury building with condominium flexibility is the most marketable story the building tells.
Pricing is apartment-specific. Floor, exposure, configuration, and renovation quality all move value in a building this small.
Closing timelines run through the condominium process. There is no co-op board admission; timing depends on the condominium's application and right-of-first-refusal process, so confirm it with building management.
Comparable buildings
If you're considering 521 Park Avenue, also evaluate:
- 40 East 66th Street — nearby prewar converted to condominium
- 1 East 66th Street — Lenox Hill cooperative at Fifth Avenue
- 500 Park Avenue — Lenox Hill condominium nearby
- 502 Park Avenue — Park Avenue condominium peer
- 530 Park Avenue — Lenox Hill cooperative peer
- 510 Park Avenue — nearby Park Avenue cooperative
More Upper East Side buildings
- 520 East 76th Street (John Jay House) — 1964 co-op by H.I. Feldman
- 520 East 86th Street — 1929 co-op by Charles A. Platt
- Parker 72nd (520 East 72nd Street) — 1963 co-op
- 524 East 72nd Street (The Belaire) — 1988 condominium by Frank Williams (Frank Williams & Associates)
- 525 East 80th Street — 1981 condominium
- 525 East 82nd Street (The Mansion House) — 1962 co-op by Philip Birnbaum & Associates
The neighborhood
For the full corridor — architecture, transit, and pricing across Upper East Side — read The Roebling Team Guide to Upper East Side.
How to read the facts on this page. Items attributed to an offering plan describe the building as it was offered at that filing — unit mix, square footage, the amenity program as planned. They are not a statement about how the building operates today. Tax and compliance figures are sourced separately to current City records and carry their own dates. House rules, staffing and fee policy can change by board resolution without any public filing: treat every policy line here as a starting point for diligence and confirm it with the managing agent. Where this page compares one building or neighborhood to another, that is our analysis of the recorded record — it names the measure, the period and the sample it rests on, and it is an observation about medians rather than a prediction about any particular apartment.
Considering a move at 521 Park Avenue?
Request a private building brief with the relevant comparable sales, current and off-market availability, and an apartment-specific view of value.
646.939.7375 · c.cohen@compass.com