CA taxpayers with $1,000,000 or more of CA AGI do not get to use the 100%/110% of prior year's taxes safe harbor to avoid underpayment penalties. They must pay in the entire current year projected tax in quarterly payments (or withholding etc.).
I cannot find such a stipulation in the federal underpayment instructions. Just want to make sure, no matter how much a taxpayer's federal AGI, the taxpayer can use the 100%/110% of prior year's taxes to calculate the underpayment penalty.
Right?