Oregon Revised Statutes State Legislative Department and Laws § 171.752

(1) Not later than April 15, for the accounting period beginning January 1 and ending March 31;

(2) Not later than July 15, for the accounting period beginning April 1 and ending June 30;

(3) Not later than October 15, for the accounting period beginning July 1 and ending September 30; and

(4) Not later than January 15 of the following calendar year, for the accounting period beginning October 1 and ending December 31.