State Apportionment Calculate, track, and record taxable income for multi-state corporations

Why choose State Apportionment

Your company may operate in multiple states, but you still have only one tax department — which means the more states you deal with, the harder it is to keep track of each state’s apportioned tax. Thomson Reuters ONESOURCE State Apportionment module helps your team handle data consistently and use standard calculation methods to streamline your entire process, from determining taxable income to filing. And our web-based software lets your team easily share information and log changes to make sure audits go smoothly.

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One system for every direct tax step

Staying on top of changing direct tax regulations is a challenge — how can technology help? Unfold the possibilities by accounting for every step of the direct tax life cycle with ONESOURCE.


What you get with our Income Tax – United States add-on

Manage data consistently

Leverage the power of automation to gather, calculate, and review state tax apportionment in one centralized system.

Calculate instantly

Determine apportionment for entities across your firm using pre-populated, yet customizable, tax rules.

Make audits easier

Keep an automatic audit trail of every change so your team can recall data, reports, and calculations at any time.

Save time

​Eliminate countless hours spent gathering and reconciling data, checking for errors, and managing separate spreadsheets.

Model and plan

Use the modeling functionality to map out different scenarios and compare your tax liability for each.

Integrate seamlessly

As part of the ONESOURCE suite, State Apportionment works with our Income Tax, Tax Provision, and Estimated Payments software.

ONESOURCE helps cut one tax department's processes in half

Hear how State Income Tax Manager LaShell Estes of WestRock Company, overcome the challenge of data with ONESOURCE State Apportionment


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