Price by Walking the Street: What California's New Algorithm Law Means for Rental Owners

After three columns on laws that shifted burdens onto rental owners, here's a different animal: the first new rental law in years that isn't aimed at you. Mostly.

AB 325 amended California's antitrust law, the Cartwright Act, to target "common pricing algorithms" — software that pools data from competing landlords and recommends rents. It's Sacramento's answer to the RealPage litigation, in which the Department of Justice alleged that landlords feeding their non-public rent rolls, occupancy rates, and lease terms into shared software — which then generated pricing recommendations everyone followed — had replaced competition with a cartel run by a machine. Whether firms collude through a handshake or an algorithm, the government argued, should make no legal difference.

If you price your rentals by knowing your block, this law is not your problem. It's your moat. But you need to know where the line sits, because some of your software may have been standing near it.

The Doc-Stamp Test

I've priced off shared transaction data my whole career, legally, and so has every agent in America. MLS sold comps have never been called a cartel. Why not?

Because of what sits underneath them: the public record. When a house sells, documentary transfer tax stamps put the price in a government file that anyone — buyer, seller, appraiser, journalist, nosy neighbor — can pull on identical terms. The MLS is just a convenient window onto facts the whole market can see. Zillow buying and republishing that data doesn't change its nature; you're paying for aggregation, not for access to secrets.

Now run rental data through the same test. Leases aren't recorded. There is no doc stamp on a signed lease. The actual rent, the concessions, the renewal terms — those live in the owner's books and nowhere else. So a dataset built from participating landlords' rent rolls fails the public test twice: the underlying facts were never public, and the pool typically isn't open to just anyone — access requires being a landlord and, in the give-to-get models, feeding your own private data in. A price tag doesn't launder private data into public data. A members-only exchange with a cover charge is still members-only.

That's the whole legal line in one question: is there a public record underneath? For sale prices, yes. For rents, no. Everything else follows.

It's Not the Data — It's the Direction It Faces

Here's the cleanest way I know to explain why comps are legal and pools are not. Data that faces the whole market — recorded sale prices, advertised asking rents, anything a prospective tenant can see — sharpens competition. Both sides get smarter, and sellers still have to guess what buyers will accept. That guessing is the competition: one owner prices low to fill fast, another holds out, a third throws in a free month. Tenants harvest the difference.

Data that faces only the sellers' side — current rents, upcoming expirations, occupancy targets, pooled in real time with a recommendation engine on top — removes the guessing. When everyone prices off everyone's books, nobody has a reason to undercut anybody, and the pooled picture of the market quietly becomes the market. The DOJ's filings described neighborhoods where most of the apartments priced off the same software: to a renter it looked like a competitive market with many landlords; functionally it was one algorithm setting rents.

Sharing what happened is transparency. Pooling what everyone is about to do, sellers-only, with a machine that turns it into a price, is a hotel-room handshake with better software.

Watch What the Vendors Did

You don't need a law degree to find the line — the software industry drew it for you, in public, through its product decisions.

I've used AppFolio for years, and I watched this happen in my own dashboard. For a long stretch, its rent guidance drew on the platform's own database — leased comps, actual rents from managed portfolios. Strong valuations, for exactly that reason. Today its pricing tool advertises a very different architecture, and the marketing copy reads like a compliance memo: comparable data aggregated exclusively from public sources, your proprietary information never factored into anyone else's pricing, and the owner reviews and sets the final price. Public comps in, private data siloed, human decision on top.

No court ordered that design, and to be clear, AppFolio hasn't been accused of anything — the lawsuits of record name other companies. But the redesign traces the legal boundary precisely: public data only, no cross-pollination between customers, and a human override instead of an auto-accepted price. When the vendors serving this industry re-engineer their products to that shape, believe them. That's where the line is.

The Audit: Do You Know What Your Software Knows?

Three questions for any pricing tool you or your manager uses. Where do the comps come from — public listings, or other customers' books? Does your own data feed anyone else's recommendation? And do you set the final price, or does the software? Public sources, siloed data, human decision: pass. Pooled private data with a recommended number: that's the architecture the DOJ sued over and AB 325 codified against — and "the software did it" is not a defense the Cartwright Act recognizes.

Walking the Street Just Became the Gold Standard

Here's the irony worth savoring. Small independent owners have always priced the way antitrust law wants everyone to price: drive the comps, watch days-on-market, read the advertised rents, know which building repainted and which one's been sitting. Talking shop with another operator over coffee is legal and always has been. Feeding both your rent rolls into a common machine is what isn't.

The big operators bought software to replace that local knowledge, and the software walked them into a federal lawsuit. Your method — eyes on the block, judgment on the number — was never at risk. AB 325 didn't restrict the independent owner. It outlawed the shortcut your biggest competitors were using, and left your edge intact.

There's no doc stamp on a lease, which means there's no rental Zestimate built on real rents, which means somebody still has to actually know the street. In this county, after four decades, that's us — and the day perfect rent data arrives, the value doesn't disappear, it just moves to where it's been heading all series long: not the number, but the execution. The compliance file, the turn, the tenant relationship. Price is becoming public. Operations never will be.

This article is general information, not legal or tax advice. Consult your attorney or CPA about your specific situation.