If you get a stock grant in California, you owe California income tax on every share that vests from a block that is awarded in CA. The income tax is prorated b

If you get a stock grant in California, you owe California income tax on every share that vests from a block that is awarded in CA. The income tax is prorated by the number of months that you were a resident in CA, relative to the vesting point. I left CA about a year after a stock award and had to pay CA state tax for 3 years after leaving (but each year the rate would decline). There's a serious WTF moment when you find this out, particularly when you pick up from CA and go to WA (a state without income tax).