In New York City, there is a 40% tax on all bonuses. I have no idea how it is in other states, I thought it was a nationwide thing.
The highest tax rate in new york state is 7.7% (if you make over $500,000). If you live in NYC you ALSO must pay city income tax which is 3.648% (if you make over 50K, 90K if you are married).
Assuming you are making over 336,550, I agree you would be subject to over 40% tax on your bonus, actually 46% (and all other income for that matter).
But for the rest of us, we may have 40% WITHHELD, but you will not necessarily owe 40% come tax time.
EDIT: I hate hijacking this thread and I'm sorry for causing this off-topic debate. If you still disagree PM me and we can talk about the topic there.