RSU tax in Florida

Florida takes nothing from a vest, but your employer still under-withholds the federal share, $2,970 of it on the example below.

What a $60,000 vest actually costs in Florida

A single filer already earning $180,000 in salary. The vest stacks on top of that, so it fills the highest brackets rather than starting at the bottom:

Withheld by your employer at 22.0%	$13,200
Federal tax the vest actually costs	$16,170
Federal shortfall, owed in April	$2,970
Florida income tax on the vest	none
Total still to find	$2,970

The withholding rate is flat, 22.0% below $1 million of supplemental pay. And takes no account of your salary. That is why the gap grows the more you earn.

The gap widens with salary

Salary	Withheld	Actually owed	Shortfall	Florida tax
$90,000	$13,200	$13,764	$564	,
$160,000	$13,200	$14,570	$1,370	,
$260,000	$13,200	$20,630	$7,430	,

How Florida treats a vest

Florida has no personal income tax, so a vest is a federal-only event here, $16,170 of federal tax on $60,000 of vesting stock, and nothing to the state.

What the same vest costs around Florida

Total income of $240,000 in the states Florida borders:

State	Its tax	vs Florida
Alabama	$11,960	+$11,960
Georgia	$12,456	+$12,456

Alabama would take $11,960 more, $11,960 against Florida's $0.
Georgia would take $12,456 more, $12,456 against Florida's $0.

RSU questions in Florida

Should I sell at vest?

Selling immediately raises the cash for the $2,970 you still owe and leaves no capital gain, because the sale price equals the price you were already taxed on. Holding turns it into an investment decision, any further gain is a capital gain, and any fall is a loss you take on shares you were already taxed on at the higher value.

I moved to Florida mid-vest, who taxes it?

Both states, split by workdays. The income is allocated across the vesting period, not assigned to wherever you happened to live on the vesting date. The state you left can still claim its share, and California, New York and Massachusetts pursue it hardest.