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    Tax research

    US Tax Research AI

    Research US federal and state tax questions with Cassandra. Explore Internal Revenue Code issues, IRS guidance and cross-border facts in a professional workspace.

    Tax researchUnited States

    A focused starting point
    for your next piece of work.

    Tax research for United States, covering legislation, regulatory guidance and practical questions.

    Use the workflow below to prepare the relevant facts and identify the parts of the output that need your review.

    Ways to use United States Tax

    • Explore Internal Revenue Code and Treasury Regulations questions for a US taxpayer.
    • Compare federal treatment with the relevant state's tax position.
    • Investigate treaty, withholding and cross-border exposure for clients with US connections.

    What to bring to the conversation

    • Taxpayer classification, US state, taxable year, residency and international connections.
    • Relevant transaction, assessment, notice or event dates and the supporting documents.
    • The United States research question, other jurisdictions involved and the memo, comparison or action list your team needs.

    What to check before using the output

    • Check federal and state treatment separately, including the relevant court circuit and tax year.
    • Verify cited provisions, judgments, figures and effective dates against the sources for the matter.

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    Professional tools. Professional judgement.

    AI outputs need independent verification. Engine access depends on your plan and current platform settings. Catalogue reviewed 19 October 2026.

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