Updated August 16, 2026
There are three real paths: negotiate a buyout among the owners, agree to a sale everyone can live with, or file a partition action and let a court force the outcome. California law gives a co-owner holding an undivided interest the right to seek partition, and because an apartment building generally cannot be physically divided, a partition of a building almost always means partition by sale — the court orders the property sold and the proceeds divided. That right is what makes the negotiation work. The owner who wants out has a real remedy, which is exactly why most of these situations settle before anyone files.
Partition is expensive, slow, and value-destructive. Court costs, attorney fees on both sides, a referee appointed to conduct the sale, and a sale process that signals distress to every buyer who sees it. A court-supervised sale rarely achieves what a properly marketed sale achieves.
Its real function is leverage. Once the co-owners understand that one of them can compel a sale, the conversation usually shifts from whether to how — and "how" is where value is preserved.
Buyout of the departing owner. The most common resolution. The remaining owners refinance or contribute capital and purchase the exiting interest.
An agreed open-market sale. Everyone participates, the building is marketed properly, proceeds are split per the ownership percentages.
A structured exit over time. Sometimes the answer is a sale in two years with agreed terms, allowing one owner to complete a plan or reach a tax milestone.
A 1031 exchange split. With careful advance structuring, co-owners can sometimes separate so that one takes cash and another exchanges into a replacement property. This has to be planned well ahead of the sale and requires specialist tax advice — it is not something to attempt on a short timeline.
Before anyone talks about court, read the documents. Many co-ownership situations already contain the answer and nobody has looked in years.
LLC operating agreement or partnership agreement. Frequently contains transfer restrictions, rights of first refusal, buy-sell provisions, valuation mechanisms, and deadlock procedures.
A buy-sell or shotgun clause. One owner names a price and the other chooses to buy or sell at it. Blunt, effective, and worth knowing about before you trigger it.
A tenancy-in-common agreement. Co-tenants sometimes have a written agreement governing sale and partition rights, including waivers.
Nothing at all. Common with inherited property held by siblings as tenants in common. That is the situation where partition rights are the default framework.
In most of these disputes the parties are not actually arguing about whether to sell. They are arguing about what the building is worth. The owner who wants out believes it is worth more; the owner who wants to stay believes it is worth less — and each belief conveniently matches their position.
An independent, documented, market-based valuation is the fastest way through. Not an assessed value, not a number from a website, not a relative's opinion. A defensible value grounded in actual closed comparable sales, presented to everyone at once, resolves more co-ownership disputes than any legal maneuver — because it removes the thing each side was arguing from.
Where the parties still disagree, testing the market is the definitive answer. An actual marketing process produces actual offers, and offers are not opinions.
Two features make it sharper here. First, many of these buildings are held on very old Prop 13 bases, so a buyout that triggers reassessment has consequences the parties should model before they choose a structure. Second, on a rent-stabilized building the value gap between in-place income and market rents is large, and co-owners frequently disagree about how much of that upside should be reflected in the price — one is valuing the income, the other is valuing the potential. Naming that disagreement explicitly usually helps more than arguing about a single number.
Read the operating or co-ownership agreement first — it may already contain a buy-sell mechanism and a valuation method. Then get an independent, documented valuation and put it in front of everyone simultaneously. Treat partition as the backstop that makes negotiation credible, not as the plan, because a court-supervised sale generally returns less to everyone than a properly marketed one. If the parties genuinely cannot agree on value, test the market — real offers end the argument.
Can one owner sell just their share?
An undivided interest can technically be transferred, but almost nobody wants to buy a minority interest in a privately held apartment building with co-owners who did not choose them. The realistic buyer is another co-owner, which is why the internal buyout is the usual path.
How long does a partition action take?
Considerably longer than a normal sale, and the timeline depends on the court and the level of contest. Between the litigation and the referee-supervised sale, the combination of delay, cost, and a sale process that signals distress is why it is a remedy of last resort.
Does a buyout trigger property tax reassessment?
It can, depending on the ownership structure and how much of the interest changes hands. On a building held at a decades-old assessed value, that is a large enough number to shape the structure — model it with a CPA before agreeing to terms.
Michael Sterman is Senior Managing Director Investments at Marcus & Millichap.
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