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Practical tax and accounting explainers.
Canada CPA • Email & Phone Consultations • Direct CPA Access
Tax, CRA, advisory, and accounting support from a focused CPA practice.
Work directly with Cathy Yuan, CPA, CGA, CIA, MBA for practical guidance on corporate tax, personal tax issues, GST/HST, CRA matters, accounting support, and financial decision support.
25+ years in finance, accounting, and tax
Focused CPA practice
English & Mandarin
OSA CPA Professional Corporation is built for clients who want personal CPA support — not a rotating team. The practice is online-first and designed around tax clarity, CRA response, practical accounting support, and better business decisions.
OSA CPA refers to OSA CPA Professional Corporation, an Ontario CPA practice in Canada led by Cathy Yuan, CPA, CGA, CIA, MBA. The firm is also known as One Step Accounting and serves individuals, self-employed clients, and small business owners across Ontario by email and phone.
Tax & CRA Help
Practical CPA support for tax filing, CRA letters, and tax uncertainty.
When tax rules, deadlines, or CRA correspondence feel unclear, OSA CPA helps you understand the issue, organize the information, and choose the next practical step — with direct CPA guidance from Cathy Yuan.
This section focuses on the services Canadians most often need when a tax return becomes more than a simple filing.
CRA Review / Audit SupportOrganize supporting documents, prepare responses, and communicate clearly when CRA requests information or opens a review.
CRA Notice & Reassessment ReviewReview CRA letters, Notices of Assessment, reassessments, balances owing, denied credits, and document requests in plain language.
Tax Planning & Compliance CheckupYear-round review to reduce surprises, identify gaps, and keep personal, self-employed, or corporate tax matters on track.
Corporate Tax & Owner-Manager PlanningT2 corporate tax support, shareholder/owner-manager tax questions, salary/dividend considerations, and year-end planning.
Self-Employed & Small Business TaxPractical help with business income, expenses, GST/HST questions, instalments, recordkeeping, and year-end tax readiness.
Personal Tax Filing & Advisory ReviewSupport for personal tax returns, credits, deductions, investment income, rental income, prior-year issues, and questions before filing.
Advisory & Analysis
Outsourced finance analysis for organizations that need experienced support.
As flexible and freelance professional support becomes more common, organizations do not always need to wait until a full-time hire is available. When a qualified finance analyst is difficult to find, or when leadership needs experienced support for a specific reporting, budgeting, forecasting, or variance review need, outsourced CPA-level finance analysis can be a practical option.
OSA CPA provides this type of support for universities, mining companies, healthcare organizations, nonprofits, government-funded organizations, and established businesses — helping leadership understand performance, risks, trends, and next steps through clear analysis, useful reporting, and experienced judgment.
Financial Reporting & AnalysisPrepare and analyze financial reports so leadership can understand results, trends, risks, and opportunities.
Budgeting & Forecasting SupportSupport budget preparation, forecast updates, and forward-looking planning for departments, projects, or operating units.
Variance AnalysisCompare actual results against budget, forecast, and prior periods, with clear commentary on key drivers and changes.
Management ReportingTurn financial data into monthly, quarterly, or project-based reporting that supports management decisions.
Financial Models & Decision SupportBuild or review practical models for business cases, funding decisions, cost review, capital planning, or operational analysis.
Process & Control ImprovementHelp identify reporting gaps, strengthen finance processes, and improve the reliability of financial information.
Accounting & Tax
Keep your books, filings, and tax obligations organized.
Many business owners only discover accounting problems when it is time to file tax: missing receipts, unreconciled accounts, GST/HST questions, payroll deadlines, shareholder loan issues, or unclear CRA balances. OSA CPA helps organize the accounting foundation so tax filings are accurate, deadlines are clearer, and business owners know where they stand.
Corporate Tax / T2
Corporate tax filings, year-end adjustments, owner-manager questions, and practical tax planning for incorporated businesses.
Year-End Accounting Review
Review bookkeeping, reconciliations, expenses, shareholder transactions, and supporting records before tax filing.
GST/HST Filing & Review
Support with GST/HST returns, input tax credits, filing deadlines, registration questions, and CRA account balances.
Payroll & Source Deductions
Help with payroll compliance, source deductions, remittance questions, T4 slips, and year-end payroll reporting.
T-Slips & Owner Payments
Prepare or review T4/T5 slips, dividends, salary, shareholder draws, and owner-manager compensation records.
Bookkeeping Cleanup for Tax
Organize and clean up accounting records so returns can be prepared accurately and with fewer last-minute surprises.
Knowledge Hub
Cathy Yuan’s CPA insights, real case sharing, and CRA policy analysis.
Read practical reflections from Cathy Yuan, CPA, CGA, CIA, MBA, including anonymous client situations, professional observations, CRA policy notes, compliance reminders, and video explainers. The focus is learning from real issues — what happened, what records mattered, and what taxpayers or business owners can prepare before seeking advice.
General education only. Case sharing is anonymized and does not replace advice for your specific situation. For personalized guidance, please contact Cathy directly.
Case Sharing
Anonymous real-world situations and lessons.
Tax & CRA Updates
CRA reminders, deadlines, and policy notes.
Video Explainers
Short videos with key takeaways.
Featured from Knowledge Hub
Visit Knowledge Hub →
CRA Support
Small Business
Owner-Manager
What to do when you receive a CRA review letter
Understand the request, organize records, and respond with care.
GST/HST records small businesses should keep
Common documents that help support filing and review questions.
Salary, dividends, and owner payment records
Key documentation considerations before year-end tax filing.
About Me
A CPA practice built from real experience and a desire to make accounting feel clearer.
I am Cathy Yuan, CPA, CGA, CIA, MBA, founder of OSA CPA Professional Corporation.
My professional background spans mining, healthcare, education, IT, government, and owner-managed business environments. Across these settings, I gained practical experience in financial analysis, accounting, tax, cost awareness, internal controls, audit, compliance, budgeting, reporting, and business analysis.
Those experiences shaped how I work today. I see numbers not only as records, but as information that helps people understand risk, make decisions, and move forward with more confidence.
Over time, I also saw how stressful tax, CRA, and accounting issues can feel for individuals and business owners. A letter from CRA, unclear records, a filing question, or a business decision can feel overwhelming when people are not sure what to do next.
That is why I started OSA CPA — One Step Accounting. The idea is simple: help clients take the next clear step, one step at a time.
Outside my professional work, I enjoy reading, watching movies, and travelling with my family. I also value lifelong learning and staying open to new ideas, including emerging AI technology. Building this website has been part of that learning journey — starting with very limited IT knowledge and gradually learning how to use new tools to bring OSA CPA’s online presence to life. I have also been involved in long-term volunteer work, including CPA mentorship and supporting new CPAs and young professionals as they build confidence, judgment, and direction in their careers.
LinkedIn ProfileView my LinkedIn profile to review my professional background and credentials.
Professional foundation
Built broad experience across several industries, with a focus on financial analysis, accounting, tax, cost, controls, audit, compliance, reporting, and business decision support.
A desire to help more directly
Wanted to work more closely with individuals and business owners who need clear CPA guidance, especially when CRA issues, tax uncertainty, or confusing records create stress.
OSA CPA began part-time
OSA CPA Professional Corporation began as a part-time practice built around direct communication, careful review, and practical next steps.
OSA CPA became full-time
OSA CPA became my full-time professional focus, allowing me to support clients more directly through tax, CRA, accounting, and advisory matters.
How We Start
A clear first step before any engagement.
1
Send an inquiry
Briefly describe your tax, CRA, accounting, or advisory question.
2
CPA review
Cathy reviews the situation to understand scope, urgency, and service fit.
3
Email or phone consultation
Discuss the issue by email or phone and clarify the practical next step.
4
Clear next steps
Receive guidance on whether filing support, CRA response, accounting review, or advisory work is needed.
FAQ
Common questions before contacting OSA CPA.
Clear answers about CRA support, tax filing, small-business accounting, online consultation, and how OSA CPA works with clients.
Do I work directly with Cathy Yuan, CPA, CGA, CIA, MBA?
Yes. OSA CPA is a focused CPA practice, so clients work directly with Cathy Yuan, CPA, CGA, CIA, MBA, rather than being passed between departments or a rotating team.
Can OSA CPA help if I receive a CRA letter or review request?
Yes. OSA CPA can help review the letter, identify what CRA is asking for, organize supporting documents, and prepare a clear response.
Can you help with CRA reassessments or audit support?
Yes. OSA CPA can review Notices of Assessment, reassessments, balances, document requests, and CRA review or audit issues to help determine practical next steps.
Do you provide personal tax support?
Yes. OSA CPA can assist with personal tax filing questions, prior-year issues, deductions, credits, rental income, investment income, and CRA-related personal tax concerns.
Do you support small businesses and self-employed individuals?
Yes. OSA CPA can help with business income, deductible expenses, GST/HST questions, instalments, records, and year-end tax readiness.
Can OSA CPA help incorporated businesses with T2 corporate tax?
Yes. OSA CPA can assist with corporate tax filings, year-end accounting review, shareholder transactions, salary/dividend questions, and owner-manager planning.
Can you help with GST/HST and payroll questions?
Yes. OSA CPA can help with GST/HST returns, input tax credits, registration questions, payroll remittances, source deductions, T4/T5 slips, and CRA account balances.
Are consultations available online or by phone?
Yes. OSA CPA is an online-first practice and offers consultation by email or phone, based on the nature of the issue and client preference.
What should I prepare before contacting OSA CPA?
Briefly describe your issue and gather relevant CRA letters, tax notices, prior filings, bookkeeping records, payroll or GST/HST records, and the questions you want reviewed.
Contact
Request a free consultation.
Share a short summary of what you need help with. OSA CPA will review your inquiry and respond with the appropriate next step.