Entities we file for
| Entity | Federal return | Due date (calendar year) | Notes |
|---|---|---|---|
| S corporation | Form 1120-S | 15 March | K-1s to shareholders; reasonable compensation is the perennial issue |
| Partnership / multi-member LLC | Form 1065 | 15 March | K-1s to partners; watch guaranteed payments |
| C corporation | Form 1120 | 15 April | Less common for small firms, but not extinct |
| Single-member LLC | Schedule C on Form 1040 | 15 April | Disregarded federally, still visible to Oregon and local taxes |
The Oregon and Portland layer
This is where most out-of-area preparers get lost, and it is worth being specific about which tax is which — we untangle all four side by side on the Portland business tax page.
- Oregon CAT — a commercial activity tax on Oregon-sourced receipts, not on profit. A business can owe CAT in a year it loses money.
- Portland Business License Tax — city-level, on net income apportioned to Portland.
- Multnomah County Business Income Tax — county-level, separate return, filed alongside the city tax.
- Metro SHS business tax — a further 1% on business income within the Metro district.
- Oregon PTE-E election — a pass-through entity elective tax that can move state tax above the federal SALT cap for the right businesses.
What we need from you
- Year-end financials — or bookkeeping catch-up if the books are not there yet
- Prior-year return and depreciation schedules
- Payroll reports and any 1099s issued
- Ownership changes, distributions and loans during the year
- Where your revenue was actually sourced, which drives CAT and city apportionment
My books are a mess. Can you still file?
Yes, but the books come first — a return built on unreconciled accounts is a guess. Katie handles catch-up bookkeeping and we sequence it so the return still lands on time or on a properly filed extension.
Should my LLC elect S-corp status?
Sometimes. It helps when reasonable compensation, payroll costs and admin overhead pencil out — and it does nothing for CAT or the Portland local business taxes. We work the numbers on the entity selection page.
Do you file in Washington too?
Where required. Washington has no business income tax but does have B&O tax on gross receipts, which trips up Oregon businesses selling into Clark County.
When should we start?
For a 15 March deadline, January. Waiting until late February usually means an extension, which is fine for filing but does not extend the time to pay.
Talk it through before filing season starts
Start with a complimentary 15-minute introductory call about your situation and whether we are a good fit. No tax advice is given on that call.
Written by
Enrolled Agent, Oregon Licensed Tax Consultant
License number: Enrolled Agent 00160070-EA · Oregon Licensed Tax Consultant 35746-C
Heather has spent more than a decade preparing individual and business returns across the Portland metro and the Columbia Gorge, and holds unlimited rights to represent taxpayers before the IRS.
Last reviewed
This page is general information about Oregon, Washington and federal tax rules, not advice about your own return. Thresholds and rates change every year. Figures were verified as of August 2026 — check the linked official sources, or talk to us about your situation.