A CRA Review Letter vs an Audit: Which One You Got, What Each Can Do, and How Cross-Border Filers Should Answer

The CRA's mail sorts into two families that taxpayers routinely confuse, at cost in both directions — panicking at reviews, under-reacting to audits. The review family: the pre-assessment review (your return held before assessment while a claim is checked), the processing review (post-assessment document requests on selected claims), and the matching program (your return compared against the slips filed about you — T4s, T5s, NR4s — with proposed adjustments where they disagree). Reviews are narrow by design: a letter names the line or claim — the foreign tax credit, the tuition transfer, the moving expenses, the dependant amount — asks for supporting documents by a stated deadline (typically 30 days, extendable on request), and resolves when you send them: claim supported, assessment stands; support missing or inadequate, the claim is adjusted and the reassessment tells you so, with your objection rights intact. No books-and-records examination, no interviews, no year-wide scope — a review answered completely and on time is correspondence, not conflict. The audit family is the CRA's deeper power: a named auditor, an engagement letter identifying years and scope, authority to examine books, records, and bank accounts, questionnaires and interviews, and — in the cross-border files — the specialized international and offshore programs whose queries arrive with foreign-reporting appetites (T1135 details, foreign account statements, the corporate structures behind T106 profiles). Audits run months, produce proposal letters inviting representations before reassessment, and warrant professional representation essentially always. Cross-border filers meet both families more often for structural reasons: foreign tax credits are perennial review targets (the matching program can't see Canadian-side proof of US taxes — the review letter is how it asks); foreign income and the T1135 feed the risk models; NR4/1042-S cross-border slips mismatch in predictable ways (gross-versus-net, FX, timing); and the answers that satisfy quickly are the ones built like the US-side playbook — the claim mapped to documents, foreign paper explained in a line each, conversions shown, sent complete and trackably within the clock. The escalation ladder behind both: disagree with a reassessment (from either family) via a notice of objection within 90 days — the formal dispute channel with its own independent review — and onward to Tax Court where warranted; interest runs regardless while amounts are unpaid, which shapes the pay-under-protest arithmetic on larger disputes; and the one conversion to avoid is self-inflicted — the ignored review letter that becomes a denied claim, a reassessment, and a collections file, three escalations manufactured from an unanswered request for receipts.

Key takeaways

• Read the letter's family first: a document request naming a specific line or slip mismatch = review (narrow, resolvable by mail); an engagement letter with an auditor's name, years, and scope = audit (broad powers, get representation). The response strategy follows the family.
• Reviews are won by completeness on time: the named claim, the supporting documents, a one-page cover mapping each document to the claim, sent trackably inside the deadline (extensions granted when asked early). Partial or late responses become adjustments by default.
• Cross-border claims should be filed review-ready: the foreign tax credit's proof (the US return, account transcript or payment proof, the FX workpaper) assembled at filing time, because the review letter asking for exactly that package is a matter of when.
• Matching mismatches are explained, not just contested: the NR4 that reports gross while your return shows net, the slip in USD converted at a different date — the response reconciles the numbers line by line rather than asserting correctness.
• Audits get professionals and process: representation from the engagement letter, scope managed in writing, interviews prepared, the proposal letter answered with representations before reassessment — the review-letter habits scaled up with counsel involved for anything touching the offshore programs.
• The objection clock is the real safety net: 90 days from any reassessment to object (with limited extension relief after); objections preserve every argument the response stage didn't win — calendar it the day any reassessment arrives.

The response templates worth keeping

Two skeletons serve nearly every letter. Review response: (1) reference line quoting the letter's request; (2) enclosure list, numbered; (3) one paragraph per requested item mapping enclosure to claim, with conversions shown; (4) contact block. Mismatch response: (1) the CRA's figure, your figure, and the difference; (2) the reconciliation table (gross/net, FX, timing); (3) the enclosures proving each reconciling item. Both fit on a page, both resolve the majority of letters in one round — and both exist as templates precisely because cross-border filers will use them annually, not once.

Worked example

A Windsor commuter (Canadian resident, Michigan employer) receives two CRA letters in one season. Letter one, processing review: support the C$21,400 foreign tax credit. Her filing-time folder already holds the package — the 1040 and W-2, the IRS account transcript showing tax paid, the FX workpaper — sent with a one-page map inside two weeks: credit confirmed, file closed in six. Letter two, matching program: an NR4 from a US broker reports gross investment income exceeding her T1's figure by C$3,100. The reconciliation response shows the difference is withholding tax and a December-versus-January payment date — a table, two statements, one FX schedule: adjustment cancelled. Her colleague's contrasting year: the same credit review ignored for two months ("I'll get to it") became a full credit denial and a C$21,000 reassessment with interest — recovered eventually through a notice of objection with the identical documents, plus four months of collections letters and a garnishment warning that the original 30-day window would have cost her a stamp to avoid. Same claims, same proof — the difference was treating the review as the correspondence it was, on the schedule it demanded.

Official sources

"It is important to emphasize that when we select your return for review, that it does not represent a tax audit." The CRA checks returns through its Pre-assessment Review, Processing Review, and Matching programs — the Matching Program comparing a return "to information provided by third-party sources, such as employers or financial institutions." — Canada Revenue Agency, Review of your tax return, https://www.canada.ca/en/revenue-agency/services/tax/individuals/topics/about-your-tax-return/review-your-tax-return-cra.html

For penalties, the CRA "will consider a request only if it relates to a tax year or fiscal period ending in any of the 10 calendar years before the year in which you make a request"; for interest, it considers "only the amounts that accrued during the 10 calendar years before the year in which you make a request." Requested on Form RC4288. — Canada Revenue Agency, Cancel or waive penalties and interest, https://www.canada.ca/en/revenue-agency/services/about-canada-revenue-agency-cra/complaints-disputes/cancel-waive-penalties-interest.html

Practitioner note

CRA letters are triaged by family before they're answered: reviews are document requests that reward speed and mapping, audits are engagements that warrant representation, and the cross-border filer will receive the former annually enough to justify templates. Our standing setup is filing-time folders for the claims the review programs always ask about — the foreign tax credit above all — so the letter that finds our clients finds the package already built.

See also: For how far back the CRA and IRS can reassess, see how far back the CRA and IRS can reassess; and browse every cross-border tax topic guide, organized by situation.

Next step

Fairlight prepares the CRA correspondence program — letter triage, review responses with mapped enclosures and reconciliation tables, audit representation from the engagement letter, and objection-deadline management on any reassessment. See cross-border pricing or book a call.