Assuming billionaires were going to get a special tax, how would you actually determine how much to tax them? Sure some would be straightforward like Musk where it’s entirely derived from a few companies with known ownership stakes, but what about all the others?
We don’t even know the names of most of the billionaires. With all the games they can play to hide money, now made even easier thanks to the changes Trump made in his first few months, how would you even figure out who and what amount to tax? They don’t have a normal salary or easily documented income like everyone else.
I was going to write about how an existing tax agency (the California FTB) is already aggressive at tracking down high-earning residents that leave the state – whether in-fact or on-paper – in order to collect precisely what the state is owed per the tax code. That is, the FTB already engages and challenges the precise amounts that these former residents write on their final California tax returns, with some more spectacular results being some incredibly detailed timelines for when someone finally stops being a resident in California, as defined in state law.
But then I noticed that because of California’s proposed wealth tax (aka Billionaire Tax) on the November 2026 ballot, the SF Chronicle has already started a series of articles to answer the specific what-and-hows of the wealth tax. This is the first article, pertaining to enforcement, and it agrees that the FTB would be capable of pursuing any high-wealth individuals that the proposal would tax. https://www.sfchronicle.com/california/article/ca-billionaire-tax-mechanism-21330110.php
This proposed tax in California is written as a one-time tax, so the question of whether high-wealthy people could flee the state is nearly irrelevant, because either they’re subject to the tax or they’re beyond the reach of the US courts (eg Venus). Almost. The remaining questions are legal in nature, and don’t really change how the tax would be pursued. Whether FTB simply hires a dedicated team or outsources to private investigators, the task is still straightforward: follow the money.
Unlike civil lawsuit plaintiffs, who have more limited means of chasing down a defendant’s assets in order to get paid on a judgement, the California tax authorities enjoy the benefit of the subpoena power, that can be used to compel companies and banks to tell the tax authorities about where and how wealth is being held. It is, after all, a core power of a US state to administer a tax, especially when the tax is authorized directly from the sovereign power (ie the citizenry). Any other result would conflict with the very purpose of a republic: to unyieldingly serve the people.