Employers in Oregon must conform with these state rules relating to filing income tax withholding returns.
Periodic Returns. Form OQ must be filed by the last day of the month following the quarter for employers whose federal liability is less than $2,500 in the current quarter.
Employers whose federal liability was $50,000 or less during the 12-month look back period ending June 30 of the prior year must make payments by the 15th of the following month.
Employers whose federal liability was more than $50,000 during the look back period must make payments within three banking days of the semiweekly period (Wednesday-Friday, Saturday-Tuesday).
Accelerated deposit rules apply if accumulated undeposited federal taxes total $100,000 or more; payment must be made by the close of the next banking day
Annual Reconciliation Returns. Form WR due by February 28.