I received my bonus this week. While the federal government withholds supplemental income (read: bonus) at a somewhat reasonable rate of 22% (assuming your bonus is separate from your normal paycheck), NY state withholds at a rate of 9.62% which is HIGHER than the highest marginal tax rate (8.82%). NY City withholds at a rate of 4.25%... again higher than the highest rate of 3.87%.
This means that every single person receiving supplemental income in NY will overpay the State and/or city every single year. It is a forced interest-free loan.