A tax firm's balance sheet lists its software licenses, its office lease, its accounts receivable. It does not list the fact that one reviewer knows why a client's capital account has carried an unusual basis adjustment since 2019, or that a single senior manager is the only person left who remembers why an aggressive position was dropped two seasons ago rather than fought. That knowledge is real and it is load-bearing. It just belongs to no line on any ledger — which is exactly why a firm discovers it is missing only after the person holding it has already gone.
Why the rules assume someone is still there to ask
Circular 230 § 10.22(b) lets a practitioner rely on someone else's work without independently re-checking it, but only if the practitioner used reasonable care in engaging, training and supervising that person. AICPA's Statements on Standards for Tax Services go further in their own way: under section 1.2, Knowledge of Errors, revised effective January 1, 2024, a member who becomes aware of an error on a client's previously filed return must promptly advise the client. Both rules presuppose that the person who would recognize the error, or who trained the junior reviewer, is still at the firm to do it. Neither has anything to say about what happens to that presumption the week after the person it depends on resigns.
The pipeline that used to replace them is shrinking
This isn't a slow leak a firm can plan around indefinitely. U.S. schools awarded 55,152 accounting bachelor's and master's degrees in the 2023-2024 academic year, down 6.6% from the year before — itself a smaller drop than the 9.6% decline the year before that, so the pipeline is still shrinking, just more slowly. The CPA Exam pipeline moved the other direction, sharply: 42,626 new candidates started the exam in 2023, and only 28,082 did in 2024.
New CPA Exam candidates, by year
The pipeline that replaces a departing reviewer shrank by a third in one year
Put the two trends together and the shortage isn't only about head count. Every departing reviewer takes a specific, unwritten body of client knowledge with them, and the number of people available to absorb it by sitting next to them for a few seasons is falling at the same time. A firm that loses a ten-year reviewer today has a thinner bench to hand that knowledge to than it had five years ago, and a smaller chance the replacement stays long enough to build an equivalent body of their own.
What the law actually requires a firm to keep
It's worth being precise about what's regulated here, because it's less than it sounds. 26 CFR § 1.6107-1 requires a preparer to retain a completed copy of the return, or at minimum a list of the taxpayer's name and identifying number, for three years after the return period closes. That's the entire federal retention floor on the output. Nothing in it reaches the reasoning that produced the output — why a position was taken, why a diagnostic was overridden, why this year's treatment matched or departed from last year's.
Circular 230 § 10.33 comes closest to a structural duty: a tax advisor "with responsibility for overseeing a firm's practice" should keep its procedures consistent with best practices, firm-wide. It's aspirational, not enforced like § 10.34 — but it's the one place the rules put firm-wide consistency on someone by title, not on whoever happens to remember.
What a firm can do structurally, rather than hope the right person stays
None of the four moves below require new hires or new software, though a review-and-memory layer makes each of them easier to sustain past the first busy season. They're ordered the way the gap actually opens: a judgment call gets made, it goes somewhere, and then it either survives the handoff to next year's reviewer or it doesn't.
Capture the judgment, not just the outcome
Write down why a position was taken or a diagnostic overridden, at the moment the call is made — not a reconstruction months later.
Attach it to the return line it explains
A note filed separately from the line it's about is a note nobody searching that line will ever find.
Make it findable by someone other than its author
If locating last year's reasoning requires asking the person who wrote it, the firm hasn't actually preserved anything.
Carry it forward across tax seasons, not just within one
A note that doesn't survive past April is a note that has to be re-derived from scratch the next time the same question comes up.
Where Pernee fits
Every gap above is the same shape: a judgment call made once, in a place only its author can easily find again. Pernee is a review-and-memory layer that attaches a reviewer's reasoning to the return line it explains and keeps it there across the tax seasons a firm actually revisits it — so the knowledge a departing reviewer built doesn't have to leave with them.
Keep a reviewer's judgment after the reviewer leaves
See how Pernee carries review reasoning across tax seasons and staff changes, inside the tools your firm already runs.
