On one hand, I can see the need for it since the billionaires have constantly been receiving tax breaks which is part of the reason for them becoming billionaires. Those tax cuts took money away from helping the rest of the people of California.
On the other hand, it's a one-time tax and it will help only for one year. After that, we're back to the same problem of needing more state revenue.
The major problem I see in this proposition is how do you calculate who has a billion dollars. Do you use total gross aggregate value of property, income, investments, deferred compensation, etc.., or do you take into account their net value? Also, would the assets in other states/countries or investments outside California be included in the valuation?
I favor a graduated income tax in that the more you make the more you pay in state taxes. Instead of a one year tax on billionaires we should raise the tax on anyone making more than $1 million dollars a year. The state income tax would remain the same on the first million dollars and would increase by 2% from $1 to $5 million and up to 5% on anything over $5 million dollars. This way, the state would increase their revenue without raising taxes on the middle/lower income groups and the increased revenue would continue for years.
Just my two cents from a non-billionaire.