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643 Knickerbocker Avenue, Brooklyn, NY 11221

BBL 3033650109 (Borough 3, Block 3365, Lot 109) · BIN 3076917 · Last updated:

Summary · as of October 31, 2026

643 Knickerbocker Avenue (Brooklyn, NY 11221; tax lot BBL 3033650109) is a 5-unit walk-up apartment building (building class C2: walk-up apartments, five or six families), built around 1915, on a 1,750 sq ft lot zoned R6. City tax records list the owner as 4MB FUND TENTH REALTY INC.; per ACRIS, a deed to this owner dated March 15, 2018 lists a price of $875,000. The Department of Finance's final market value for tax year 2027 is $1,073,000. As of October 31, 2026, NYC Open Data shows three OATH tickets with an unpaid balance. (Source: NYC Open Data — DOB, HPD, OATH, DOF, DCP and ACRIS datasets — compiled by NYC Property Facts.)

Owner of record
4MB FUND TENTH REALTY INC.
Building class
C2 · Walk-up apartments, five or six families
Year built · units
1915 · 5 res.
Lot area · zoning
1,750 sq ft · R6
Market value (DOF)
$1,073,000 FY2027
Last priced deed
$875,000 · 2018-03-15
BBL
3033650109
BIN
3076917

How to cite: NYC Property Facts, “643 Knickerbocker Avenue, Brooklyn, NY 11221 (BBL 3033650109)”, data as of 2026-10-31, https://nycpropertyfacts.com/ny/brooklyn/643-knickerbocker-avenue-3033650109. Source: NYC Open Data.

Lot & building

Basic facts about the tax lot and building from the city’s PLUTO database.

Owner (as listed by the city)
4MB FUND TENTH REALTY INC.The owner name on the city’s tax records. It can lag behind recent sales and is often an LLC.
Building class
C2 – Walk-up apartments, five or six familiesThe Department of Finance’s category for what kind of building this is.
Land use
Multi-family walk-up buildingsCity Planning’s broad category of how the lot is used.
Year built
1915Often an estimate for older buildings. Major alteration recorded: 2019.
Floors
4
Units
5 residential / 5 totalResidential units are apartments; total includes stores and offices.
Buildings on lot
1
Lot size
1,750 sq ft (20 ft × 87.5 ft)
Building floor area
3,898 sq ft
Zoning
R6The zoning district sets what can be built and used here. Residential district.
Built vs. allowed density (FAR)
2.23 built / 2.43 max residentialFloor Area Ratio = building floor area ÷ lot area. If built FAR is below the maximum, zoning may allow more floor area (other rules apply).
Identifiers
BBL 3033650109 (Borough 3, Block 3365, Lot 109) · BIN 3076917BBL identifies the tax lot; BIN identifies each building (from DOB/HPD/footprint records).

Source: PLUTO (Dept. of City Planning) — city dataset updated 2026-08-24; data as of 2026-11-01; Building Footprints — city dataset updated 2026-10-25; data as of 2026-11-01

Tax assessment

How the Department of Finance values this lot for property tax.

Market value (tax year 2027, final roll)
$1,073,000The Department of Finance’s estimate of value for tax purposes. It is not an appraisal and is often far from the sale price.
Assessed value
$482,850The portion of market value that taxes are calculated on (capped by law for small homes).
Taxable value (final)
$137,839Assessed value minus any exemptions.
Tax class
Tax class 2A – residential rental, 4–6 units
Tax yearRollMarket valueAssessed valueTax class
2027Final$1,073,000$482,8502A
2026Final$920,000$414,0002A
2025Final$897,600$403,9202A

Source: DOF Property Valuation and Assessment Data — city dataset updated 2026-09-14; data as of 2026-11-01

Sales & deed history 4

Deeds recorded with the City Register (ACRIS). A deed transfers ownership. A $0 or very low price usually means a transfer between related parties, an estate, or a refinance-related transfer, not a market sale. This is not a title search; mortgages, liens and other documents are not shown.

DateTypePriceSeller (grantor)Buyer (grantee)Doc ID
2018-03-15DEED$875,000De Montas, Nora; Montas , Nora4mb Fund Tenth Realty Inc.2018032300422001
1969-07-23DEED$0 / not statedSepulveda CalebS&R Brokers IncBK_6930034900435
1969-07-14DEED$0 / not statedS&R Brokers IncDemontas Nora; Demontas RafelBK_6930034700568
1967-04-13DEED$0 / not statedBarbera Mary; Barbera SalvatoreSepulveda CalebBK_6730040000178

Source: ACRIS Real Property Master — city dataset updated 2026-10-08; data as of 2026-11-01; ACRIS Real Property Legals — city dataset updated 2026-10-08; data as of 2026-11-01; ACRIS Real Property Parties — city dataset updated 2026-10-08; data as of 2026-11-01

DOB job filings 0 open of 5

A “job” is an application to the Department of Buildings to do construction work. A job marked Permitted, not signed off had a work permit issued but the city has no record of final sign-off (inspection/completion). Old jobs left in this state are common and appear in buyer and lender due diligence; the work may or may not have been done.

StatusJob #TypeFiledEst. cost
Not open
LOC Issued · 2020-12-28
B00098783-I1
DOB NOW
Alteration2018-11-13$5,000
Not open
LOC Issued · 2020-12-28
B00098772-I1
DOB NOW
Alteration2018-11-12$5,000
Not open
PLAN EXAM - DISAPPROVED · 2018-09-26
321843378
BIS
A3 – Minor alteration (one type of work)2018-09-25—
Not open
SIGNED OFF · 2020-11-05
321707079
BIS
A2 – Alteration with multiple work types (no change to use/occupancy)2018-06-13$5,000
Not open
SIGNED OFF · 2025-09-03
321707131
BIS
A1 – Major alteration (changes use, egress or occupancy)2018-03-05$851,459

Source: DOB NOW: Build – Job Application Filings — city dataset updated 2026-10-31; data as of 2026-11-01; DOB Job Application Filings (BIS) — city dataset updated 2026-10-30; data as of 2026-10-31

Work permits 7

Individual permits issued under DOB jobs (one job can have several permits, e.g. plumbing and construction). Permit expiration alone does not mean the job was completed or signed off.

IssuedExpiresJob #WorkPermit status
2019-04-122020-10-31321707131
BIS
AlterationISSUED (renewal)
2019-02-262020-02-26321707131
BIS
Plumbing / PlumbingISSUED (initial)
2019-01-142019-09-21B00098783-I1
DOB NOW
Supported Scaffold
PROPOSED INSTALLATION OF TEMPORARY PIPE SCAFFOLD AS PER PLANS. WORK SHALL COMPLY WITH CHAPTER #33 OF THE NYC BUILDING CODE. NO CHANGE IN USE, OCCUPANCY, OR EGRE
Signed-off
2019-01-112019-09-21B00098772-I1
DOB NOW
Sidewalk Shed
PROPOSED INSTALLATION OF HEAVY DUTY SIDEWALK SHED AS PER PLANS. LIVE LOAD 300 LBS PER SQUARE FEET. SIDEWALK SHED SHALL COMPLY WITH CHAPTER #33 OF THE NYC BUILDI
Signed-off
2018-11-142019-09-21B00098772-I1
DOB NOW
Sidewalk Shed
PROPOSED INSTALLATION OF HEAVY DUTY SIDEWALK SHED AS PER PLANS. LIVE LOAD 300 LBS PER SQUARE FEET. SIDEWALK SHED SHALL COMPLY WITH CHAPTER #33 OF THE NYC BUILDI
Signed-off
2018-11-142019-04-04321707131
BIS
AlterationISSUED (initial)
2018-11-132019-09-21B00098783-I1
DOB NOW
Supported Scaffold
PROPOSED INSTALLATION OF TEMPORARY PIPE SCAFFOLD AS PER PLANS. WORK SHALL COMPLY WITH CHAPTER #33 OF THE NYC BUILDING CODE. NO CHANGE IN USE, OCCUPANCY, OR EGRE
Signed-off

Source: DOB NOW: Build – Approved Permits — city dataset updated 2026-10-31; data as of 2026-11-01; DOB Permit Issuance (BIS) — city dataset updated 2026-10-31; data as of 2026-10-31

DOB violations 0 active of 0

Violations issued by the Department of Buildings for building-code or zoning conditions. Active means DOB has not recorded the violation as resolved or dismissed. Many active DOB violations are old (e.g. elevator or boiler inspection paperwork).

No records found in this dataset for this lot.

Source: DOB Violations — city dataset updated 2026-10-31; data as of 2026-11-01

ECB violations (DOB) 0 active of 3

DOB violations that go to a hearing at OATH (formerly the Environmental Control Board) and can carry fines. Active or Resolved follows the DOB violation status field. The hearing status is about the hearing and its penalty: written off means the city stopped collecting the fine, not that the condition was corrected. A balance due is a fine the city says is unpaid.

StatusIssuedSeverityWhat it was forPenalty / paid / balanceECB #
Resolved
Hearing: CURED/IN-VIO · Certification: CURE ACCEPTED
2019-03-21CLASS - 2FAILURE TO PROVIDE ACCEPTED SITE SAFETY PLAN,AT TIME OF INSPECTION.AT TIME OF INSPECTION ON AN ACTIVE SITE OF A 4 STORY ALT-1,FILED INITIALLY ON 11/14/18,REQUIRING A SITE SAFETY PLAN;UPON REQUEST OF SITE SAFETY$0 / $0 / $035404934M
Resolved
Hearing: DISMISSED · Certification: N/A - DISMISSED
2019-03-21CLASS - 1WORK DOES NOT CONFORM TO APPROVED CONFORM TO APPROVED CONSTRUCTION DUCENTS AND OR APPROVED AMENDMENTS.AT TIME OF INSPECTION ON AN ACTIVE SITE OF A 4-STORY ALT-1,I OBSERVED STRUCTURAL WORK WAS COMPLETED CONTRARY$0 / $0 / $035404935Y
Resolved
Hearing: DISMISSED · Certification: N/A - DISMISSED
2019-03-21CLASS - 1CONSTRUCTION SUPERINTENDENT LOGBOOK.INADEQUATE AT TIME OF INSPECTION ON AN ACTIVE SITE OF A 4-STORY ALT-1 I OBSERVED PERSONNEL AND A COMPETENT PERSON ON SITE-UNERGOING CONSTRUCTION OPERATIONS,WITH UNSAFE CONDIT$0 / $0 / $035404933K

Source: DOB ECB Violations — city dataset updated 2026-10-31; data as of 2026-11-01

OATH tickets (all agencies) 3 unpaid of 11

Summonses heard at the Office of Administrative Trials and Hearings, from agencies like Sanitation, Buildings, Fire and Health, linked to this lot’s block and lot. Default means the respondent did not appear at the hearing, which typically results in the maximum penalty. Tickets may be issued to tenants or businesses at the address, not just the owner. DOB ECB tickets appear here too.

StatusDateAgencyChargeRespondentImposed / paid / balanceTicket #
Unpaid balance Default
DOCKETED · DEFAULTED
2025-07-12Dos - Enforcement AgentsLOOSE RUBBISH 1ST OCCURRENCE4MB FUND TENTH REALTY INC$300 / $0 / $300049245093J
Unpaid balance Default
DOCKETED · DEFAULTED
2024-12-06Dos - Enforcement AgentsSPILLAGE FROM A RECEPTACLE 1ST OFFENSE4MB FUND TENTH REALTY INC$100 / $0 / $100048733557P
Unpaid balance Default
DOCKETED · DEFAULTED
2021-02-26Sanitation OthersFAILURE TO CLEAN 18 INCHES INTO STREET4MB FUND TENTH REALTY INC$300 / $0 / $300047102683Z
No balance due Default
PAID IN FULL · DEFAULTED
2022-05-01Pcs - DohmhFAIL TO ELIMINATE RODENT INFESTATION SHOWN BY ACTIVE RODENT SIGNS 1ST4MB FUND TENTH REALTY INC$600 / $600 / $00802256667
No balance due
HEARING COMPLETED · DISMISSED
2019-03-21Dept. Of BuildingsWORK DOES NOT CONFORM TO APPROVED CONST. DOCUMENTS AND OR APPROVED AMECITY BUILDERS INC$0 / $0 / $0035404935Y
No balance due
HEARING COMPLETED · IN VIOLATION
2019-03-21Dept. Of BuildingsFAIL TO PROVIDE APPROVED OR ACCEPTED CONSTRUCTION DOCS AT JOB SITECITY BUILDERS INC$0 / $0 / $0035404934M
No balance due
HEARING COMPLETED · DISMISSED
2019-03-21Dept. Of BuildingsCONSTRUCTION SUPERINTENDENT FAILED TO PERFORM DUTIES PER CODEMOHAMMAD AMR$0 / $0 / $0035404933K
No balance due
HEARING COMPLETED · DISMISSED
2017-09-09Sanitation OthersIMPROPER DISPOSAL BEDDING 1ST OFFENSEMONTAS$0 / $0 / $00195899065
No balance due
HEARING COMPLETED · DISMISSED
2016-10-07Sanitation OthersSTORAGE OF RECEPTACLESMONTAS— / — / —0192852450
No balance due
HEARING COMPLETED · IN VIOLATION
2009-06-20Sanitation OthersFAILURE TO CLEAN 18 INCHES INTO STREETENG$100 / $100 / —0170700036
No balance due
PAID IN FULL
2007-04-21Dos - Enforcement AgentsNON-RECYCLABLES LEFT IN RECYCLING CONTAINER FOR COLLECTIONNORA DE MONTAS$25 / $25 / —041450054Z

Source: OATH Hearings Division Case Status — city dataset updated 2026-11-01; data as of 2026-11-01

HPD registration & contacts

Owners of most rental buildings must register with the Department of Housing Preservation and Development each year and list an owner and managing agent.

No HPD registration found. Registration is required for buildings with 3 or more apartments (and for 1–2 family homes where neither the owner nor family lives there).

Source: HPD Multiple Dwelling Registrations — city dataset updated 2026-10-28; data as of 2026-11-01; HPD Registration Contacts — city dataset updated 2026-10-28; data as of 2026-11-01

HPD housing-code violations 0 open of 0

Violations HPD inspectors issued for conditions in residential buildings (heat, leaks, mold, pests, lead paint, etc.). Class letters show how serious: Class A – non-hazardous (HPD gives 90 days to correct); Class B – hazardous (30 days to correct); Class C – immediately hazardous (24 hours to correct for most conditions); Class I – information / order (e.g. orders to register, lead or other administrative orders). Open means HPD has not recorded the condition as corrected.

No records found in this dataset for this lot.

Source: HPD Housing Maintenance Code Violations — city dataset updated 2026-10-31; data as of 2026-11-01

HPD complaints 0

Complaints tenants or others made to HPD (usually via 311) about housing conditions, from 2019 onward. A complaint is not a violation; HPD may inspect and issue one.

No records found in this dataset for this lot.

Source: HPD Housing Maintenance Code Complaints and Problems — city dataset updated 2026-11-01; data as of 2026-11-01

311 requests (last 12 months) 0

Recent 311 service requests the city geocoded to this lot: noise, illegal parking, heat, sanitation and more. Anyone can file them, so they describe activity at or near the address, not necessarily the building itself.

No records found in this dataset for this lot.

Source: 311 Service Requests from 2020 to Present — city dataset updated 2026-11-01; data as of 2026-11-01

Nearby properties

On Knickerbocker Ave

Same tax block (3365)

All properties on Knickerbocker Ave, Brooklyn · All of Brooklyn 11221 (Bedford-Stuyvesant (East))

Open-item counts as of October 31, 2026; each section lists its own dataset date. Machine-readable: JSON API · Markdown · Plain text · API & MCP docs