Every year CRA processes more than 30 million tax returns. They audit a small fraction of those, but the selection is not random. CRA uses a sophisticated risk-scoring system that flags returns matching known patterns of underreporting, error, or aggressive tax positions. Knowing what the system looks for helps you file returns that stay below the threshold and respond intelligently if CRA does come knocking. This guide explains the eight most common audit triggers we see at Finsight Accounting and the practical steps you can take to reduce your risk.
1. Income That Does Not Match Industry Averages
CRA maintains detailed benchmarks for every industry and profession in Canada. If your reported net business income is significantly below the average for your industry, postal code, and reporting size, the system flags your return for review. A Calgary plumbing contractor reporting $35,000 of net income while the industry average is $85,000 will draw attention. The same applies to a real estate agent reporting low net commissions in a year when MLS data shows active transactions. CRA does not require you to be average, but you should be ready to explain why your numbers differ. Legitimate reasons such as a partial year of operations, illness, or one-time large expenses are acceptable. Unexplained deviations are not.
2. Large Deductions Relative to Income
Deductions that consume an unusually high percentage of reported income are a top audit trigger. Examples include a sole proprietor reporting $80,000 of gross income and claiming $70,000 of expenses, leaving almost nothing to tax. Or an employee using a T2200 to claim $20,000 of work-from-home expenses against a $90,000 salary. These ratios fall outside normal patterns and prompt CRA to ask for documentation. The deduction may be entirely legitimate, but expect to prove it. Keep every receipt, mileage log, and supporting record for at least six years after filing.
3. Repeated Business Losses
A business that reports losses year after year, especially while the owner has a separate source of income, raises the question of whether it is a genuine commercial activity. CRA distinguishes between a business (a profit-seeking activity) and a hobby (a personal pursuit). If your Calgary side business has lost money for three or more consecutive years, CRA may challenge whether the losses are deductible against your other income at all. Document your business plan, your strategy for reaching profitability, your marketing efforts, and any external factors that explain the losses. A real business losing money for legitimate reasons is still a business. A hobby being filed as a business is not.
4. Cash-Intensive Businesses
Restaurants, bars, salons, taxi and rideshare operators, contractors, landscapers, and other cash-heavy businesses face higher audit scrutiny because the opportunity for unreported income is greater. CRA's specialized audit teams use indirect methods to estimate true revenue. They look at supplier purchases (a restaurant ordering large quantities of food relative to reported sales), bank deposits, lifestyle indicators, and even social media. If you run a cash business in Calgary, use point-of-sale systems that create an audit trail, deposit all revenue to a business account, separate personal and business expenses cleanly, and reconcile monthly. The discipline that protects you in an audit also runs a better business.
5. Rental Property Income and Expenses
Rental properties are a perennial CRA focus. Common triggers include expenses claimed without rental income reported (you cannot deduct property expenses if the property is not generating income), claiming personal-use portions as deductible, capital expenses incorrectly deducted as current expenses (a roof replacement is capital, a repair to a single shingle is current), and failing to report imputed income when a property is rented to a family member below market rent. With short-term rental platforms (Airbnb, VRBO) growing in Calgary, CRA also receives data directly from platforms and matches it against reported income. Underreporting Airbnb income is a fast track to a reassessment.
6. Self-Employed Tax Filings With High-Risk Categories
Self-employed individuals face higher audit rates than employees because more of the tax calculation depends on self-reported figures. Within self-employment, certain categories attract extra attention: home office expenses, vehicle expenses, meals and entertainment, and travel. A self-employed Calgary consultant claiming all four categories at high percentages will rank higher in CRA's risk model than a comparable contractor who claims minimal home office and no entertainment. The deductions may be appropriate, but they elevate audit risk. Document everything and be ready to defend the business purpose of each expense.
7. Inconsistencies Between T1 and Information Slips
CRA receives information slips directly from every employer, financial institution, brokerage, and government program. T4 employment income, T5 investment income, T3 trust income, T4A pension and self-employed income, T5008 securities transactions: all of these arrive at CRA before you file your return. When the income you report does not match the totals CRA has on file, the return is flagged automatically. The fix is straightforward: download your Auto-fill My Return data from CRA My Account before completing your T1 every year. This ensures every slip CRA has on you is reflected in your filed return. Calgary taxpayers who skip this step and miss a slip almost always receive a Notice of Reassessment within six months.
8. Aggressive Tax Planning and Promoted Schemes
CRA aggressively pursues promoted tax shelters, charitable donation schemes that claim receipts exceeding actual contributions, and arrangements that appear designed primarily to reduce tax rather than serve a real economic purpose. Common examples include leveraged donation arrangements (avoid entirely), private corporation income-splitting that does not meet the TOSI exceptions, and reorganizations executed without legitimate business purpose. If a tax strategy seems too good to be true and is being marketed by a non-CPA promoter, it almost always triggers an audit and almost always loses at the Tax Court of Canada level. Stick to recognized tax planning strategies executed by a licensed CPA.
Industries CRA Watches Closely in Alberta
Several Alberta industries face elevated audit attention based on historical noncompliance patterns: oil and gas consultants and contractors (high-income, often with significant deduction claims), real estate investors and agents, construction trades, restaurants and food service, taxi and rideshare operators, and cannabis-related businesses. Operating in these industries does not mean you will be audited, but it does mean your documentation needs to be tight. Use a Calgary CPA familiar with your industry to set up your books correctly from the start.
What an Audit Actually Looks Like
Most CRA audits in Calgary are desk audits, conducted by mail or through CRA's online portal. The auditor requests specific records, you provide them, and the audit concludes with either no change, a reassessment, or a small adjustment. Field audits are less common and involve a CRA auditor visiting your home or business to review records on site. Both audit types follow a structured process: opening contact, document gathering, analysis, proposed adjustments, your response, and a final reassessment. A CPA represents you throughout, communicates with the auditor on your behalf, and protects your interests at each step.
How to Reduce Your Audit Risk
Filing a return that does not match CRA's flags is the simplest way to avoid an audit. Report all income (including all T-slip income, foreign income, crypto gains, and side business revenue). Use the Auto-fill My Return service every year. Keep deductions reasonable and well-documented. If your business has unusual numbers, attach an explanation to your return rather than waiting for CRA to ask. Use a CPA to prepare returns where business income, rental income, or significant deductions are involved. The cost of professional preparation is small compared to the cost of an audit reassessment plus interest plus penalties.
If You Are Audited
An audit notification is not a verdict. Many audits result in no change or minor adjustments. The keys to a good outcome are responding within deadlines, providing organized documentation, communicating only through a CPA, and never assuming the auditor's first proposed adjustment is final. Audit results can be negotiated, objected to, and appealed. At Finsight Accounting we have represented Calgary taxpayers in audits ranging from simple personal reviews to multi-year corporate audits. Early professional involvement consistently produces better outcomes than waiting until adjustments are proposed.
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Finsight Accounting CPA
This article was prepared by the CPA team at Finsight Accounting Professional Corporation, a licensed CPA firm based in Calgary, AB. Content is for general information purposes only and does not constitute professional tax advice. Consult a CPA for advice specific to your situation.