An accounting firm should use the weeks after October 15 to set a written client data rule and test AI on one tax task.
The timing comes from the federal tax calendar. The Internal Revenue Service lets an individual request an extension by the April tax filing due date. The extension gives until October 15 to file "without penalties". The filing season is the busy months of work before the next April due date. A test run in the weeks after October 15 finishes before that filing season starts.
Many accounting firms already use AI tools, meaning software that reads documents and drafts text. Wolters Kluwer Tax & Accounting commissioned a survey of 2,768 tax and accounting professionals. The survey ran online from April 23 to May 27, 2025. Respondents came from firms of all sizes worldwide. CPA Practice Advisor, a trade publication, summarized the survey in October 2025.
In the Wolters Kluwer survey, 72 percent of firms used AI at least weekly.
A second survey compared organizations with and without an AI strategy. Thomson Reuters sells software and tools to legal, tax, accounting and compliance professionals. Its Future of Professionals Report 2025 drew 2,275 responses in February and March 2025. Respondents worked in legal, risk, compliance, tax, accounting, audit and trade, in firms and in company departments.
Organizations with a visible AI strategy were 3.5 times as likely to report at least one form of payoff from AI. The comparison group was organizations with no significant plans for AI. Thomson Reuters gives the 3.5 times figure for all respondents, with no split for accounting firms.
The client data rule starts from federal law. Section 7216 of the Internal Revenue Code covers what a client provides for a tax return. Disclosing that information knowingly or recklessly is a crime for a tax preparer. It is also a crime to use that information knowingly or recklessly for any purpose other than preparing the return. Treasury regulations list the disclosures and uses that the law still allows.
So the firm's lawyer should confirm in writing whether the law allows client files to go into the AI tool the firm plans to test. The client data rule then tells staff which AI tools they may use with client files, and for which tasks. Staff who already use AI tools on their own learn the firm's limits before the filing season starts.
The test should cover one step of the work on returns the firm has already filed this year. Sorting the documents a client sends in, such as wage statements and brokerage forms, is one step a tax partner can pick. The tax partner chooses 50 filed returns and runs their documents through the AI tool. Staff then compare the tool's work with what the team did during this year's filing season.
The comparison counts two things: errors in the tool's work, and staff hours on that step, taken from the firm's own time records. The firm pays for the test from its own budget and bills no client for it. The 50 returns are already filed. So the test runs outside any client deadline.
What to do first:
- Firm's lawyer: confirm in writing, by October 23, whether the law allows client files to go into the AI tool the firm plans to test.
- Chief operating officer: issue the client data rule, naming the AI tools staff may use with client files, by October 31.
- Tax partner: run the test on 50 filed returns and report errors and staff hours by December 15.
- Managing partner: decide by January 5 whether the tool is used in the next filing season.
A firm built from acquired practices can run the same test in each practice. Each practice reads its result against its own time records.
