Tax Outsourcing for CPA Firms: What to Evaluate Before the 2027 Filing Season
Published October 8, 2026
Introduction
For CPA firms considering tax outsourcing before the 2027 filing season, the most useful questions concern who will do the work, how it will be reviewed, how client information will be handled, and how much time the arrangement will actually return to the firm.
October is a practical time to capture those questions while the demands of extension season are still visible. Which returns required the most partner involvement? Where did work wait? Which tasks could another qualified professional handle with clear instructions?
Those answers provide a starting point for evaluating providers. A productive outsourcing relationship begins with a defined need and evidence that the provider can meet it.
Start with the work your firm needs help completing
Before requesting proposals, identify the constraint you want to address. A firm with a preparation backlog needs different support from one whose returns are waiting for technical review.
Choose a specific group of engagements to evaluate. That might include individual returns with investment activity, recurring business returns, or work that requires experience with a particular industry. Describe the complexity, expected volume, software, and documentation available.
Be equally clear about what will remain with your team, including client communication, technical decisions, final approval, and filing.
This turns “we need more capacity” into a scope that a provider can assess and your firm can measure.
Distinguish workflow software from preparation support
A tax workflow platform may help organize documents, route assignments, and track deadlines. Preparation support adds people who perform specified work. Some providers combine both.
Ask the provider to demonstrate exactly what happens after an engagement enters its system. Does the service organize source documents, prepare the return, provide technical review, or offer access to someone who answers questions? Which of those services are included?
A platform with a help desk is different from an engagement staffed by tax professionals. Clarifying that distinction early makes proposals easier to compare.
SAM's guide to software for scaling tax preparation workflows explains how workflow tools support the work surrounding preparation and review.
Verify who prepares and reviews your returns
Ask about the people assigned to your work, including their credentials, relevant experience, location, and supervision. If the provider uses subcontractors, understand whether the same standards apply to them.
The IRS distinguishes a preparer tax identification number from professional credentials such as CPA licensure and enrolled agent status. A PTIN alone does not establish that someone is a CPA or EA.
Credentials are one part of the evaluation. Experience with your return types and client circumstances matters, too. Someone who regularly prepares straightforward individual returns may need additional support for a complex partnership engagement.
Request a clear explanation of how assignments are matched to experience and who handles questions beyond the preparer's expertise.
Define what “reviewed” means
A proposal may include review without explaining its depth. Ask whether that review covers source-document reconciliation, tax treatment, workpaper support, diagnostics, or a narrower set of checks.
Request a sample deliverable using fictional or appropriately redacted information. Look for supporting workpapers, understandable notes, and a clear record of unresolved questions.
The engagement should establish:
- Who prepares the return and who reviews it.
- How technical questions reach your firm.
- Who makes corrections and whether they carry additional fees.
- Who approves the completed work and handles e-filing.
- What support is available if questions arise after delivery.
Evaluate the provider's review alongside the review your firm will still perform. That remaining effort belongs in both the capacity plan and the cost comparison.
Evaluate data handling before transferring client files
Ask where information is stored and accessed, who can retrieve it, and whether subcontractors or other services receive it. Confirm how access is removed when an assignment or relationship ends.
Request documentation covering access controls, secure transfers, retention, deletion, and incident notification. If the service uses AI, ask whether client information enters third-party models and how it may be retained or reused.
Separately, assess disclosure requirements for the proposed arrangement. The IRS Section 7216 Information Center explains the rules governing preparers' use and disclosure of tax return information, including consent requirements and exceptions. Confirm the applicable requirements before sharing information.
Test the workflow your staff will actually use
Have the provider walk through a representative engagement from submission to return of the completed file. Use the software versions and document formats your team expects to use.
Confirm what counts as a complete submission and when the turnaround clock starts. Ask what happens when documents are missing, the client submits a correction, or your firm needs to change the scope.
Also establish how the provider communicates delays and how your team can escalate an approaching deadline.
An advertised turnaround time is easier to evaluate when both parties agree on its starting point, exclusions, and deliverable.
Compare the total cost of completing the work
The quoted preparation fee is only one part of the economics. Include internal time for organizing submissions, answering questions, reviewing returned work, and resolving corrections.
Ask about charges for additional states, complex schedules, amended work, expedited service, and implementation. Review minimum commitments, cancellation terms, and how pricing changes when the scope expands.
For each proposed engagement type, compare:
Provider fees + internal coordination and review cost + any additional charges.
Use that alongside turnaround and quality measures. A lower fee may leave your team with more work; a higher fee may include services your firm does not need.
Run a limited pilot before expanding
Choose a small set of engagements that reflects the work you intend to outsource. A pilot made up only of the easiest returns will provide limited evidence about more demanding assignments.
Agree on success measures before work begins. Track internal hours, delivery against agreed timelines, review corrections, and how quickly technical questions are resolved. Separate corrections caused by preparation from changes caused by new client information.
After the pilot, ask your reviewers whether the work was sufficiently documented and your operations team whether coordination was manageable. Expand only where the results support it.
How SAM fits into the evaluation
For firms considering domestic preparation support, SAM provides U.S.-based licensed CPAs and EAs for tax preparation, with review included. Under SAM's process, the firm retains responsibility for reviewing and e-filing completed returns using its own tax software license.
The same evaluation applies: identify suitable engagements, confirm the scope, and measure the internal effort required to complete them.
Conclusion
A useful tax outsourcing evaluation ends with a clear understanding of the people, work, responsibilities, and cost involved.
Capture this season's capacity issues now, then use them to design a focused pilot before the 2027 filing season. The results will give your firm a stronger basis for deciding what to delegate and how to manage the relationship.
