As a co-op shareholder you can deduct your allocated share of the building’s property taxes and mortgage interest on Schedule A, the same categories a house or condo owner claims, plus the interest on any personal share loan you took out to buy your shares. For 2026, deductible mortgage debt is capped at $750,000 across all your qualifying loans, and the state and local tax deduction is capped at $40,400 ($20,200 if married filing separately). These are the core co-op tax deductions, and getting the full benefit depends on understanding how the pass-through works and what your co-op reports to you.
Why a Shareholder Can Deduct at All
When you buy into a co-op, you don’t get a deed. You get shares of stock in a corporation and a proprietary lease that lets you occupy a specific unit. The corporation holds title to the building, pays the property tax bill, and services the blanket mortgage. Your monthly maintenance covers your portion of those costs along with operating expenses.
Section 216 of the Internal Revenue Code lets the corporation pass two categories of expense through to shareholders: property taxes and mortgage interest. Your share of each is based on the number of shares allocated to your unit divided by total shares outstanding. The co-op tells you what those numbers are.1Office of the Law Revision Counsel. 26 USC 216 – Deduction of Taxes, Interest, and Business Depreciation by Cooperative Housing Corporation Tenant-Stockholder
Your Share of the Property Tax Bill
The cooperative pays the property tax bill for the entire building and land. Your proportionate share is deductible on Schedule A on the same line where a traditional homeowner reports property taxes. You don’t write a check to the taxing authority yourself; the co-op does, and you claim your allocated portion.
That deduction feeds into the SALT cap. For 2026 the cap is $40,400 for most filers and $20,200 for married filing separately, and it covers state and local income taxes, sales taxes, and property taxes combined.2Office of the Law Revision Counsel. 26 USC 164 – Taxes If your state income tax plus your co-op property tax share already sits above $40,400, additional property tax payments give you nothing more.
The cap phases down at higher incomes. Once modified adjusted gross income exceeds $505,000 ($252,500 for married filing separately), the cap shrinks by 30 cents for every dollar above the threshold, but it never drops below $10,000.2Office of the Law Revision Counsel. 26 USC 164 – Taxes
Two Sources of Mortgage Interest
Co-op owners often have two streams of deductible mortgage interest. Missing one is the most common tax mistake in co-op ownership.
Your Share of the Blanket Mortgage
The corporation carries a blanket mortgage on the whole building. Your proportionate share of the interest the corporation pays is deductible, calculated the same way as the property tax share.3Internal Revenue Service. Publication 936 – Home Mortgage Interest Deduction That share is baked into your monthly maintenance.
Your Personal Share Loan
Most buyers finance their shares with a personal share loan (sometimes called a co-op loan). The IRS treats debt secured by co-op stock the same as a mortgage secured by a house. If local law or co-op rules prevent the stock from being pledged as collateral, the debt still qualifies as long as the proceeds went to buying the shares.4Office of the Law Revision Counsel. 26 USC 163 – Interest Interest on this loan is deductible as qualified residence interest on Schedule A, separate from the blanket mortgage interest.
The $750,000 Combined Cap
Your total deductible mortgage debt across both sources is capped at $750,000 ($375,000 for married filing separately).4Office of the Law Revision Counsel. 26 USC 163 – Interest Combine your personal share loan balance with your allocated share of the blanket mortgage to check whether you’re over. Ask the co-op for your share of the building debt so you can do the math.3Internal Revenue Service. Publication 936 – Home Mortgage Interest Deduction A mortgage on a second home counts against the same $750,000 ceiling.
Will Itemizing Actually Help You?
Every deduction covered here is an itemized deduction. It only helps if your total itemized deductions exceed the standard deduction. For 2026 the standard deduction is $32,200 for married couples filing jointly, $16,100 for single filers and married filing separately, and $24,150 for heads of household.5Internal Revenue Service. IRS Releases Tax Inflation Adjustments for Tax Year 2026, Including Amendments from the One, Big, Beautiful Bill
In expensive markets the numbers clear that threshold easily. If your property tax share is $8,000 and your combined mortgage interest (blanket plus share loan) is $15,000, you’re already at $23,000 before adding state income taxes or charitable gifts. A single filer in that position benefits from itemizing. Shareholders with modest share loans and low maintenance in less expensive markets should run the numbers first.
What Your Co-op Sends You at Tax Time
Your co-op files Form 1098 reporting your share of the building’s mortgage interest if the amount is $600 or more for the year.6Internal Revenue Service. Instructions for Form 1098 You should also receive an annual statement from the co-op showing your deductible share of property taxes. Your personal share loan lender issues its own Form 1098 for the interest you paid on that debt. Use both. The figures on those statements are your ceiling; you cannot deduct more than what the co-op and your lender report.
What Isn’t Deductible
Not every dollar of your maintenance produces a deduction. The deductible portion is often less than half of the total payment. The rest covers staff payroll, insurance, utilities, management fees, repairs, and reserve contributions, and none of those produce a personal deduction. Your co-op’s annual statement shows the split.
Special assessments for capital improvements, like a new roof, elevator modernization, or boiler replacement, are not deductible in the year you pay them. Add them to your basis in the shares. The higher basis reduces your taxable gain when you sell. Keep your own records; the co-op may not track this for you.
The Co-op Itself Must Qualify
Every deduction above depends on the cooperative qualifying as a “cooperative housing corporation” under Section 216 throughout the tax year. If it fails, every owner in the building loses these deductions for that year. Four tests apply:1Office of the Law Revision Counsel. 26 USC 216 – Deduction of Taxes, Interest, and Business Depreciation by Cooperative Housing Corporation Tenant-Stockholder
- The corporation has only one class of stock outstanding.
- Stockholders are entitled to occupy their units solely because they own stock.
- The corporation does not distribute earnings and profits to stockholders except during a partial or complete liquidation.
- The corporation satisfies at least one of three tests: 80% of gross income comes from tenant-stockholders (the traditional 80/20 rule), 80% of the building’s square footage is used or available for residential use by tenant-stockholders, or 90% of expenditures go toward acquiring, building, managing, or maintaining the property for tenant-stockholders.
The board’s handling of commercial rental income and building expenditures directly affects your ability to deduct.
Home Office Deduction
If you use part of your unit exclusively and regularly as your principal place of business, you can claim the home office deduction on Form 8829.7Internal Revenue Service. How Small Business Owners Can Deduct Their Home Office from Their Taxes This lets you deduct a proportional share of expenses that are otherwise nondeductible, including the operating portion of maintenance. The calculation uses office square footage divided by the unit’s total square footage. This deduction is for self-employed individuals and business owners; employees working from home generally do not qualify on their federal return.
When You Sell Your Shares
The IRS treats the sale of co-op shares the same as the sale of a principal residence. Under Section 121, you can exclude up to $250,000 of gain if you’re single, or up to $500,000 if you’re married filing jointly, provided you owned the shares and lived in the unit as your main home for at least two of the five years before the sale.8Office of the Law Revision Counsel. 26 USC 121 – Exclusion of Gain from Sale of Principal Residence Any gain above the exclusion is taxed at long-term capital gains rates.
Your basis starts with the price you paid for the shares. Add every capital improvement assessment you paid to the co-op. Add nondeductible closing costs from the original purchase, such as attorney fees and transfer taxes. Many co-ops charge a transfer fee (often called a flip tax) when shares change hands; it isn’t deductible as a property tax, but if you’re the seller it reduces your net proceeds and therefore your taxable gain.
If you rented out the unit for any period, you were entitled to depreciate the portion of your share cost allocable to the building (excluding land), and that depreciation reduced your basis. When you sell, depreciation you claimed or should have claimed is recaptured and taxed at a maximum rate of 25%, which is higher than the standard long-term capital gains rate. Renting can produce real tax savings during the rental years, and the recapture bill at sale is the trade-off.