California’s Car Sales Tax Crackdown Calls for Primary-Use Rule

California’s recent crackdown on Montana license plated luxury cars highlights that the state vehicle tax excessively relies on paperwork instead of reflecting where cars are used.

State entity agents, transport companies, and compliance services make out-of-state delivery appear legitimate on paper when it’s really a tax dodge. To combat this, California should replace the delivery-paperwork test with a primary-use rule—similar to some states’ existing aircraft tax policies—taxing vehicles based on where they’re garaged and driven during a set test period.

State prosecutors last month filed charges against a group of luxury car buyers for allegedly using Montana limited liability companies to avoid paying sales taxes for Ferraris, Aston Martins, and other high-end automobiles. In some instances, the entire scheme seemed to amount to little more than a $200 bill of lading claiming a car had been delivered out of state.

In reality, prosecutors say, the vehicles never left California. It was an almost embarrassingly low-tech fraud.

Where a car is formally delivered and stored, not where it’s used, is the bases of California’s sales tax rule. This has created a cottage industry devoted to producing the right documentation to suggest a vehicle being used in California is in Montana.

The Montana loophole exploits that California allows residents to avoid sales tax on a vehicle if it’s delivered and kept outside the state for at least 12 months. This makes sense if one assumes there’s a transient purchaser who may even be paying a use tax in their home state.

The rule was designed to accommodate legitimate out-of-state purchases. But it also creates an incentive to generate documentation showing interstate shipment—and it leads to a market of exotic car purchasers willing to pay for that service.

Entity formation services can promise quick registration in a state with no sales tax, transporters can produce fake shipping paperwork listing out-of-state delivery addresses, and storage facilities can hold vehicles long enough to create the appearance of compliance. Fraud is a predictable result under such a system.

States are responding to these out-of-state registration loopholes with increasingly aggressive enforcement. California investigators are using audits, criminal prosecutions, and license plate reader technology to identify vehicles with out-of-state registrations operating locally. Other states are experimenting with cross-agency data matching to identify residents whose vehicles are registered somewhere else.

California’s crackdown may succeed in prosecuting a few egregious cases, but the deeper lesson is that a tax system can’t hinge on something as flimsy as $200 worth of documentation.

Photographer: Chris Ricco/Getty Images for Lamborghini

Some states have already confronted a similar problem with another type of mobile asset—private aircraft. Planes, even more easily than luxury cars, can cross state lines and be registered through entities far from where they’re put in service.

Relying on delivery paperwork for aircraft would invite the same kinds of shenanigans seen in the Montana-plated vehicles schemes. Many states instead apply tax rules that focus on primary use or base location. Aircraft purchases may be subject to a defined test period during which authorities determine where a plane is being stored and operated, using operational records such as flight logs.

The goal there is to tax the aircraft where it’s being used. The same logic could apply to cars, with toll data standing in for flight logs. Dealers could be required to report sales to in-state residents regardless of delivery location, placing a vehicle on authorities’ radar and allowing them to verify compliance using objective standards such as garaging, insurance, and registration.

Toll data and red-light camera records, which provide time-stamped location evidence showing repeated driving patterns within a state, would be particularly useful. This and similar indicators would allow states to identify clear patterns of local vehicle use while relying on data that transportation agencies are already collecting—avoiding the costs, and potential privacy risks, of building new systems or tracking drivers continuously.

Statutory penalties could further reinforce such a system. If a car declared as exported were recorded on more than a set number of days within the test period, the owner could face higher fines or automatic tax liability. Clear thresholds would shift the cost-benefit calculation for would-be avoiders at the time of purchase. Rather than gambling on whether investigators would notice a Montana plate, buyers would know that routine transportation data could quickly uncover the scheme.

Some buyers could still keep a vehicle out of state during the test period to avoid the tax. But at that point, the strategy would begin to resemble genuine out-of-state ownership instead of a paperwork-driven avoidance scheme.

Ensuring the system taxes the economic reality of how the car is being used, not eliminating every theoretical opportunity for avoidance, should be the underlying policy’s real goal. After all, a car purchaser could simply opt not to buy the vehicle in California.

California’s crackdown may succeed in prosecuting a few egregious cases, but the deeper lesson is that a tax system can’t hinge on something as flimsy as $200 worth of documentation. Rather than chasing paperwork after the fact or rolling out technology that could cost as much as the state stands to recoup in lost tax revenue, the state should rely on the systems they already operate to determine where a vehicle is being used.

Andrew Leahey is an assistant professor of law at Drexel Kline School of Law, where he teaches classes on tax, technology, and regulation. Follow him on Mastodon at @andrew@esq.social.

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