Washington’s annual apportionable income form due Oct. 31


Taxpayers engaging in apportionable activities for Washington Business & Occupation (B&O) tax purposes are required to complete and file an Annual Reconciliation of Apportionable Income form (Reconciliation Form) by Oct. 31 of each year with the Washington Department of Revenue.1 The Reconciliation Form for the 2022 calendar year is due Oct. 31, 2023.




Washington apportionment


Businesses that have nexus with Washington and are engaged in apportionable business activities are required to apportion income and apply a single factor based on receipts.2 Apportionable activities include, but are not limited to, revenue taxed under the following B&O tax classifications: service and other activities; real estate broker; travel agent; international investment management services; and royalties.3 Businesses that solely report under a business classification such as Manufacturing, Wholesaling, or Retailing are not required to apportion their income and therefore are not required to file the Reconciliation Form.


A separate Reconciliation Form must be filed for each apportionable classification and separate receipts factors must be calculated for each apportionable activity or B&O tax classification.4The numerator of the receipts factor is the total apportionable receipts attributable to Washington during the calendar year.5 The denominator is the total worldwide apportionable receipts during the calendar year excluding throwout income.6 For purposes of calculating a receipts factor, throwout income is income that is not taxable in any other state and at least part of the income producing activity is performed in Washington.


Original B&O tax returns are generally due on a monthly or quarterly basis throughout the year. The Department provides taxpayers two methods for calculating taxable income, either using the receipts factor for the most recently available calendar year or using current reporting period information.7 However, when data becomes available to determine the receipts factor for the entire calendar year, taxpayers must file the Reconciliation Form to reconcile their apportionable income and obtain a refund or pay any additional tax due.8 The form must be filed regardless of which method the taxpayer uses to compute apportionment on the original returns. Interest will apply to both refunds and additional amounts due.9


To avoid any potential penalties, the Reconciliation Form must be filed and any additional tax due as a result of the reconciliation must be paid by Oct. 31 of the following year. Notably, the Reconciliation Form must be filed with the Department even if zero tax is due.






It has been our experience that taxpayers who believe they have no additional tax due often fail to file the required Reconciliation Form. The form is not listed as part of the required monthly/quarterly tax returns within the tax return section of the Department’s online filing system. Upon audit, such taxpayers are often surprised by the inclusion of the late payment penalty allowed by statute (up to 29%).10 We strongly advise taxpayers to file the required Reconciliation Form, even if they believe they have no tax due, in order to protect themselves from potential penalties upon audit.


1 WAC § 458-20-19402(602).
2 RCW § 82.04.462.
3 RCW § 82.04.460(4)(a).
4 WAC § 458-20-19402(401).
5 WAC § 458-20-19402(402)(a).
6 WAC § 458-20-19402(402)(b).
7 WAC § 458-20-19402(601).
8 WAC § 458-20-19402(602).
9 RCW § 82.04.462(4).
10 RCW § 82.32.090(1).




Tax professional standards statement

This content supports Grant Thornton LLP’s marketing of professional services and is not written tax advice directed at the particular facts and circumstances of any person. If you are interested in the topics presented herein, we encourage you to contact us or an independent tax professional to discuss their potential application to your particular situation. Nothing herein shall be construed as imposing a limitation on any person from disclosing the tax treatment or tax structure of any matter addressed herein. To the extent this content may be considered to contain written tax advice, any written advice contained in, forwarded with or attached to this content is not intended by Grant Thornton LLP to be used, and cannot be used, by any person for the purpose of avoiding penalties that may be imposed under the Internal Revenue Code.

The information contained herein is general in nature and is based on authorities that are subject to change. It is not, and should not be construed as, accounting, legal or tax advice provided by Grant Thornton LLP to the reader. This material may not be applicable to, or suitable for, the reader’s specific circumstances or needs and may require consideration of tax and nontax factors not described herein. Contact Grant Thornton LLP or other tax professionals prior to taking any action based upon this information. Changes in tax laws or other factors could affect, on a prospective or retroactive basis, the information contained herein; Grant Thornton LLP assumes no obligation to inform the reader of any such changes. All references to “§,” “Sec.,” or “§” refer to the Internal Revenue Code of 1986, as amended.


More SALT alerts