Oregon Underpayment Interest (don't overpay)

Al_Stu

Just want to let people know that in the absence of a required Form OR-10, the state will likely calculate and bill you for underpayment interest using the standard method. The standard method considers the underpayment to be evenly distributed throughout the year.

This will result in higher interest due compared to the annualized method if income is significantly near year end; such as from RMD, ROTH conversion, or other irregular income. For instance in my case more than 3 times the amount of interest compared to using the annualized method.

The interest rate for 2025 is over 9%. Don't pay even more if you don't have to.