When a Pacific Heights co-op unit changes hands, California reassesses that one unit at full cash value. If the property tax goes up as a result, the increase goes to the new shareholder alone, and the other owners in the building don't share it. So the monthly maintenance figure on a listing reflects what the seller has been paying. Your own figure can be different, and the listing doesn't show you that one.
For a buyer comparing a co-op on Washington Street or Broadway against a condo a few blocks away, this changes the math. You have to work out your monthly cost from the building's tax setup, and that setup varies from one building to the next.
Why one owner's tax increase stays with one unit
In a co-op, you never take title to an apartment. California Civil Code § 4190 defines a stock cooperative as a corporation that holds title to the property, with shareholders receiving exclusive rights to occupy a particular part of it. You buy shares and get the right to live in one unit.
Buying shares still counts as a sale for property-tax purposes. Revenue and Taxation Code § 61(i) counts a transfer of co-op stock that conveys exclusive occupancy as a change in ownership. The State Board of Equalization explained what follows in a 2007 letter to county assessors:
"The increase in property taxes is be applied only to the tenant-shareholder, lessee, or occupant of the individual unit that changed ownership. The increase is not to be prorated among other units."
A board annotation applies the same rule to a 164-unit cooperative. If the shareholders have not requested separate assessments and the reappraisal raises the tax, the corporation "must apply the resulting tax increase to only the shareholder of that unit and cannot prorate it among the other shareholders." That is BOE Annotation 170.0096. It means the building's combined tax bill gets split unevenly, with the newest owner charged for any increase the purchase triggered.
Why the seller's figure can look low
How far a buyer's maintenance moves from the seller's depends on how the new full-cash-value assessment compares with the unit's existing one. In San Francisco, prices have moved a long way. The California Association of Realtors' September 2026 report put the county's median single-family sale price at $2,054,000, up 17.4% from September 2025, with a median of 21 days on market.
That report doesn't publish a San Francisco condo median. It also has no co-op category at all; its condo and townhome figure is statewide. So co-op buyers have no public market series to check a price against, and the monthly carrying cost on the listing comes from the seller's assessment, not the buyer's. Reassessment happens at full cash value when ownership changes, so a unit that has gone a long time without selling is the most likely case for a meaningful reset.
Two buildings can send the same increase by different routes
California gives co-op shareholders an alternative to the corporation splitting one bill. Under Revenue and Taxation Code § 2188.7, as reproduced in the Board of Equalization's Assessors' Handbook, a written request can start separate assessment of each shareholder's interest. Once that is in place, it continues and binds later owners. Taxes on separately assessed interests go onto the county's secured roll.
Either way, your unit carries its own reassessment. What changes is the route the bill takes and where you look to estimate it.
| Building setup | How your share of the tax is set | What to request |
|---|---|---|
| No separate assessment election | The corporation pays the building's tax and has to charge any increase from your purchase to your unit only | The board's or managing agent's written estimate of your post-closing maintenance, showing the tax line |
| Separate assessment under § 2188.7 | Each interest is assessed on its own and goes onto the secured roll | Confirmation of the election, plus how the building's maintenance treats taxes after it |
The table is one reason two co-ops on the same Pacific Heights block can't be compared on maintenance alone. Their figures may rest on different tax structures, and each figure reflects a different seller's assessment.
A sale without a deed still leaves a paper trail
Co-op stock certificates aren't recorded with the county recorder, so the assessor can't learn about a sale the way it does for a house, by reading a grant deed. The Board of Equalization calls finding these transfers by conventional means "difficult." Since January 1, 2008, § 480.8 has let an assessor require residential co-ops to file annual ownership reports. If a project doesn't file the requested report, the assessor can send a change-of-ownership statement straight to each unit's shareholder or occupant.
Pacific Heights co-op prices do become public. When Apartment 3 at 2000 Washington St., a furnished 5,000-square-foot co-op, sold, The Real Deal reported a $15.5 million total. The publication said the sale closed April 11, 2025, at $15 million according to the transfer tax, with the seller-reported price including furnishings. The same article noted that the buyer received a lease granting occupancy, since co-op owners hold shares in the building rather than title to a unit. Down the street, the San Francisco Business Times reported in 2025 that unit 10 at 2006 Washington St. sold for $24 million.
San Francisco's transfer tax can reach transactions that happen without a deed. The city's Business and Tax Regulations Code counts as "realty sold" certain transfers of ownership interests in a legal entity that would be a change in ownership under state property-tax law. The city's transfer tax page says unrecorded legal-entity transactions need an affidavit even when no tax is due. How those provisions apply to a particular co-op share sale depends on the transaction, and it is a question for your attorney and escrow officer.
The loan has its own math
A share loan isn't a mortgage on an apartment. Under Fannie Mae's Selling Guide, it is secured by the borrower's shares and the occupancy rights in an assigned proprietary lease. Fannie allows share loans for a principal residence or a second home and doesn't allow them for investment property. In some markets, its loan-to-value calculation also counts the borrower's pro-rata share of the building's blanket mortgage.
The building gets reviewed along with the borrower. Fannie Mae requires lenders to assess whether a co-op project is acceptable, and it acknowledges that limited, inconsistently reported project data can get in the way of co-op financing. Any underlying building mortgage is paid through maintenance. In a building where the corporation allocates the tax, your reassessed tax is paid through maintenance too. A lender looking at your debt load will want your post-closing figure, not the seller's.
What to request before you write an offer
- The assessment structure. Ask whether shareholders have elected separate assessment under § 2188.7 or whether the corporation pays one bill and allocates it.
- A post-sale maintenance estimate. Request it in writing from the board or managing agent, with the property-tax portion based on your purchase rather than the seller's assessment.
- How the building reports ownership. Ask whether the assessor has requested § 480.8 reports and how the corporation handles them. That tells you how your purchase will reach the tax roll.
- Any blanket mortgage. Get its balance and terms, since that debt is paid through maintenance and can enter a lender's loan-to-value math.
- Your lender's view of the project. Confirm early that your lender will accept the building, before inspection and appraisal deadlines start running.
Questions buyers raise about co-op carrying costs
Will my purchase raise my neighbors' maintenance?
Not the property-tax part of it. State guidance says only the unit that changed ownership is reassessed, and any increase isn't spread across other units. The same rule works the other way when a neighbor sells. Their reassessment stays with their unit.
Is there an exception to reassessment?
BOE Annotation 220.0061 describes a narrow exclusion for certain government-financed or insured cooperatives with approved regulatory and occupancy agreements and qualifying limited-income buyers. Market-rate buildings like the Pacific Heights examples above don't fit that description.
Can I buy a co-op unit to rent out with a Fannie Mae loan?
Fannie Mae's guidelines don't allow co-op share loans on investment property. Eligible occupancy is limited to a principal residence or a second home.
This post is a general overview of how these rules are written. It isn't legal, tax or financial advice, so confirm how they apply to your purchase with a real estate attorney, a tax professional and your lender.
If you're comparing a co-op with a condo in Pacific Heights and want help collecting the building documents and post-sale maintenance estimates that make that comparison possible, Regina Gaspari can help you assemble them and read them alongside your offer strategy. Let's Connect.
