Key takeaways
- The entity return is Form OR-20-S, and the Oregon DOR says a S corporation doing business in Oregon pays $150 minimum excise tax that does not flow to shareholders.
- Oregon has no extension form of its own: file federal Form 7004 by the regular due date.
- Nonresident owners trigger Form OR-19 payments, due before the return itself, unless they join a composite return on Form OR-OC.
- The PTE-E election on Form OR-21 is made by filing the return, and the program now runs through tax years beginning before January 1, 2028.
- Collect the owner residency, apportionment and election documents in November, not at the March deadline.
What Oregon actually requires from an S corporation
Oregon follows the federal election, so no separate state election is needed. The Oregon DOR states that you file Form OR-20-S, and that an S corporation carrying on or doing business in Oregon must also pay the $150 minimum excise tax. That minimum is paid by the corporation and is not passed through to shareholders.
Oregon generally taxes the shareholders, not the corporation, on the income. A nonresident shareholder is taxed on the share of modified income from the federal K-1 multiplied by the apportionment percentage from Schedule OR-AP. A resident shareholder reports the full K-1 share on the Oregon individual return.
The test for who files is whether the corporation does business in Oregon or has Oregon-source income. The DOR says a corporation that is not doing business in Oregon and has no Oregon-source income does not need to file a corporation tax return, so ask the client where employees, inventory, customers and property actually are before assuming either way.
Due dates and extensions for 2026 returns
Oregon keys off the federal date. The DOR's own example: if the calendar-year federal S corporation return is due March 15, the Oregon calendar-year return is due April 15. Federal Form 1120-S is due on the 15th day of the 3rd month after year end. For tax year 2025 that was March 16, 2026, because March 15 fell on a Sunday.
For tax year 2026, March 15, 2027 is a Monday, so the federal return is due that day and the Oregon return follows on April 15, 2027. Put both dates on the client calendar, and put the Oregon payment date next to the federal one, because the minimum tax is due with the Oregon return.
The DOR says it does not have an extension form for Oregon and that you use federal Form 7004. File it by the regular federal due date. Following the same one-month offset, the Oregon extended date lands one month after the federal extended date, but read the 2026 OR-20-S instructions when they publish before you quote an exact day to a client.
An extension of time to file is not an extension of time to pay. With a $150 minimum, the payment is small, so send the Form OR-20-V voucher or pay online with the extension so it never becomes a penalty notice.
Nonresident owners: Form OR-19 or a composite return
If any owner lives outside Oregon, check this before anything else. The 2025 Form OR-19 instructions say the pass-through entity must submit payments for nonresident owners on their share of Oregon-source income, and that this does not depend on whether the entity makes any distributions. An S corporation with a nonresident owner who takes no cash still has a payment due.
Form OR-19 is due on the last day of the second month after the entity's year end. For calendar-year 2025 that was March 2, 2026. For tax year 2026 the last day of February is February 28, 2027, a Sunday, so expect March 1, 2027 and confirm in the 2026 instructions. This date comes before the Form 1120-S date, which catches firms that start the Oregon work after the federal return.
The 2025 instructions say to use the highest individual rate for individual owners, 9.9 percent for 2025, and corporate rates for C corporation owners, 6.6 percent on the first $1 million and 7.6 percent above that. Confirm the 2026 rates when the 2026 instructions publish.
Worked example using the 2025 rate: a Washington resident owns the S corporation. The K-1 shows $120,000 and Schedule OR-AP gives a 40 percent Oregon apportionment. Oregon-source income is 40 percent of the K-1 amount, and the payment is 9.9 percent of that. The same owner can instead join a composite return on Form OR-OC, or file an affidavit, and the instructions exclude owners who do either from the payment. The entity still files its own Form OR-20-S when it uses a composite return.
The PTE-E election on Form OR-21
Oregon's pass-through entity elective tax lets an S corporation pay tax at the entity level instead of the owners doing so. The election is made annually by filing Form OR-21 by the due date including extensions. The DOR gives April 15, or October 15 if an extension is requested, and says late returns are not accepted and paper returns are not accepted.
The rate is 9 percent on the first $250,000 of distributive proceeds and 9.9 percent on the amount above that. SB 1510 extends the program through tax years beginning before January 1, 2028, so 2026 and 2027 are both covered.
Estimated payments are due April 15, June 15, September 15 and January 15 after the year ends. For tax year 2026 only, the first two quarterly payments are due June 15. No underpayment interest applies if the entity pays at least 90 percent of expected tax. A payment alone does not make the election; filing the return does.
Each owner then claims a refundable credit with code 900 on Form OR-ASC or OR-ASC-NP and adds back the Oregon tax deducted at entity level with code 167. Issue the owner Form OR-21-K-1 only after the entity return is filed. The election can be revoked on or before the due date including extensions, so run the numbers before the deadline, not after.
What to collect from the client
Ask for these in November: the 2026 shareholder list with each owner's state of residence on December 31 and any move date; the federal K-1 draft; Oregon payroll, property and sales figures for Schedule OR-AP; the prior-year Oregon return; and last year's Form OR-19 payment confirmations. If residency is unclear, ask for the driver's license state and the home address on the last W-2 or 1040.
Use a decision rule per owner. If the owner is an Oregon resident, no payment applies. If the owner is nonresident, ask whether they want a composite return, will sign an affidavit, or want the entity to pay under Form OR-19. If the entity is considering PTE-E, ask each owner for a written yes or no, plus the owner's other Oregon income, before the June 15 estimated payment.
A request wording that gets answers: "Please confirm each shareholder's state of residence on December 31, 2026 and tell us whether any shareholder moved during the year. We need this by November 30 to calculate the Oregon payments due before March." Collect the answers as typed fields and the apportionment backup as uploaded files.
In Usual, a repeatable request with a yes or no condition per owner and a file upload for the apportionment backup fits this list, and the firm can duplicate it for each Oregon S corporation client. A shared spreadsheet works too if the firm tracks who has answered.
Common failure points
The most common miss is a nonresident owner who takes no distributions. The OR-19 instructions say the payment is required regardless, so no cash does not mean no payment.
The second is a federal extension filed late. The Oregon return has no separate extension form, so a Form 7004 filed after March 15 leaves both returns without an extension.
The third is the PTE-E election made by payment alone. The election exists only when Form OR-21 is filed on time, and the DOR will not accept it late.