Confirm apportionable activity
Separates service, royalty, financial, and other receipts that fall under Washington's apportionment framework.
Capability preview
Washington State Apportionment
Washington uses a single-factor receipts method for multi-state businesses. This preview explains the apportionment capability within Annual Reconciliation; receipt inputs, sourcing decisions, and the personalized factor stay inside the portal.
What is apportionment?
Apportionment is the method by which a multi-state business divides its income among the states where it operates. Washington uses a single-factor receipts method — only the receipts factor (not property or payroll) determines the portion of income taxable in Washington.
This differs from many other states that use a three-factor formula. Washington's approach was adopted to simplify compliance and reflect the economic reality of where a business's customers are located.
The rules are governed by four Washington Administrative Code sections — each addressing a different aspect of the process.
01 · Method
How apportionment works
1
Determine nexus
Under WAC 458-20-19401, substantial nexus is generally established when WA receipts exceed $100,000 in a year.
2
Attribute receipts
Use the cascading attribution rules in WAC 458-20-19402 to source service receipts, with special rules for royalties (19403) and financial institutions (19404).
3
Calculate your factor
Divide your WA-sourced receipts by your total receipts. The result is the share of apportionable income taxable in Washington.
02 · Authorities
The four apportionment rules
Each WAC section addresses a different aspect of Washington's apportionment framework.
WAC 458-20-19401
Minimum Nexus Thresholds
Sets the substantial nexus standards for apportionable activities. Nexus is generally established when WA receipts exceed $100,000 in a year.
Read full textWAC 458-20-19402
Services & Other Activities
The cascading attribution rules for sourcing service receipts — benefit of the service, customer location, billing address, and commercial-domicile fallbacks.
Read full textWAC 458-20-19403
Royalty Receipts
Sourcing rules for royalty income — where the intangible is used, marketing vs. non-marketing intangibles, and mixed-use contracts.
Read full textWAC 458-20-19404
Financial Institutions
Receipt-type-specific sourcing for loan interest, card fees, investment income, and other financial-institution receipts.
Read full textCapability preview
What Apportionment does
Within Annual Reconciliation, this capability organizes state-by-state receipts, applies Washington's attribution and throw-out rules, and keeps the resulting receipts factor with the supporting analysis.
The working interface lives in the client portal
This public page shows capabilities and deliverables only. It does not ask client questions, accept documents, or calculate a personalized result.
Attribute receipts by state
Applies the benefit-of-the-service cascade and the special rules for royalties and financial institutions.
Apply throw-out rules
Identifies receipts that stay in the denominator and those excluded because the business is not taxable in the destination state.
Calculate the receipts factor
Divides supported Washington receipts by the supported everywhere receipts used for the filing position.
What the tool produces
- A saved state-by-state receipts schedule tied to the client matter.
- The supported Washington receipts factor and the math behind it.
- The attribution and throw-out assumptions that require documentation or review.
- A direct handoff into the annual reconciliation and its filing work papers.
Need help with an advanced scenario?
Annual Reconciliation handles the receipts factor math. For per-customer sourcing analysis, benefit-of-the-service questions, royalty or financial-institution scenarios, and anything that requires reading the underlying rules against your facts — ask Solomon, our WA Tax Apportionment Assistant.
This tool is for informational and estimation purposes only and does not constitute tax advice. Results depend on your specific facts, nexus footprint, and how each jurisdiction's rules interact with WA's. Consult a qualified tax professional or reach out through the contact page before relying on any calculation for a filing decision.