An uneven source of revenue

While working Californians will earn an average of $4,000 more over the next two years, those earning over $200,000 a year, and/or selling a bunch of stock, will account for most of the $6.6 billion increase in tax revenue, according to new budget estimates.SF Gate

We are really talking about volatile assets generating these taxes. It is not $6 billion in real money, that is projected money. The problem here is certainly that budget estimators are measuring volatility based on smooth times, they will be shocked next year when that money dries up.