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Appeal guide · New York

How to appeal a commercial assessment in Nassau County

6 steps from the notice to the Nassau County Assessment Review Commission (ARC) and beyond, with the forms, exchange deadlines and mistakes that decide commercial cases here.

Deadline

Application for correction filed with ARC from the first business day of January through March 1 (the 2027/28 window opened January 2, 2026 and was extended by the County to March 31, 2026); online through AROW or on paper

Where to file

AROW (Assessment Review On the Web), ARC's online filing system for owners, commercial taxpayers and practitioners; paper applications are also accepted

Statute

RPTL §523-b (Nassau County Assessment Review Commission application procedure); RPTL Article 7 (judicial review)

The process, in order

ARC reviews commercial applications on the submitted record and supporting income data, and a hearing may be requested when the application is filed. Reviews run through the 14 months the roll is tentative; ARC can reduce an assessment but never increases one, and corrections are made before the final roll is filed on April 1.

Forms you will need

  • +ARC Form AR2, Application for Correction (property other than a one-, two- or three-family home)
  • +Income and expense statements for each year under review
  • +ASIE (Assessor's Survey of Income and Expense)
Nassau County jurisdiction hub
  1. 1

    First business day of January

    Review the tentative assessment

    Look up the parcel's tentative assessed value and class, convert it to market value at the published Class 4 level, and check the five-year transitional schedule for any increase.

  2. 2

    January to February

    Assemble the operating history

    Gather at least two years of itemized income and expense statements, the rent roll, leases and any recent purchase or financing appraisal. Reconcile the figures to the ASIE filed with the Assessor.

  3. 3

    By March 1, or the County's announced extended date

    File the AR2 with ARC

    File through AROW or on paper, stating the owner's estimate of market value and requesting a hearing if one is wanted. One application per parcel.

  4. 4

    By April 1

    File the ASIE with the Assessor

    Submit the annual Assessor's Survey of Income and Expense online. Owner-occupied commercial property still files, without income data.

  5. 5

    Through the 14 months the roll is tentative

    Respond to ARC review

    Answer ARC requests for income data and present the income and sales evidence at any hearing. ARC can reduce the assessment but never raises it.

  6. 6

    Final roll April 1; petition within 30 days (by April 30)

    Final roll and Article 7

    If ARC's correction is not acceptable, counsel commences an Article 7 certiorari proceeding in Supreme Court, Nassau County. Open petitions are often resolved through settlement with the County Attorney.

Mistakes that lose Nassau County appeals

  • Assuming the March 1 statutory date when the County has announced a different deadline, or relying on an extension that is not announced for the current roll.
  • Filing an AR2 without the itemized income and expense statements ARC's rules require for income-producing property.
  • Submitting income figures that do not match the ASIE filed with the Department of Assessment.
  • Skipping the ARC filing in a year already under certiorari, which forfeits that year's Article 7 petition.
  • Comparing market value to the tentative assessment at the wrong class level of assessment.

Evidence rules

  1. 1.Income-producing property needs itemized income and expense statements for each year under review and for not less than two years in total, and ARC can require the data before resolving a grievance.
  2. 2.Income includes amounts paid by tenants, licensees and other users (including related entities), utility and service charges, parking and signage revenue, and certain government subsidies.
  3. 3.Income and expense statements filed with ARC are confidential and generally not admissible in court except on the County's behalf.
  4. 4.The annual ASIE filing with the Department of Assessment is due April 1 and must be filed online; the County has sought penalties of a percentage of market value for non-filing, which have been challenged in court.

Frequently asked

Why does Nassau's assessed value look so small relative to market value?

Nassau assesses at a fractional level set for each class. On the 2027/28 roll Class 4 commercial property is at 1% of market value, so a $25 million shopping center carries a tentative assessed value of about $250,000.

When is the commercial grievance deadline?

The statutory window runs from the first business day of January through March 1. The County extended the 2027/28 window to March 31, 2026, so confirm the announced date each year before filing.

How long do I have to file an Article 7 petition in Nassau?

30 days after the final roll is filed on April 1, which makes April 30 the deadline for the 2027/28 roll. A timely ARC application is required first.

Is the ASIE the same as the ARC income statement?

No. The ASIE is an annual income and expense survey filed online with the Department of Assessment by April 1 under Administrative Code §6-30.0. ARC's application separately calls for itemized income and expenses for the years under review.

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