Business Registration with the CRA — Montreal CPA Firm Near You: Complete 4-Page Guide to Business Numbers (BN), CRA Program Accounts, GST/HST, Payroll, and Corporate Compliance

Every Canadian business—whether you’re a sole proprietor, corporation, partnership, online seller, freelancer, or non-resident operating in Canada—must understand how to register with the Canada Revenue Agency (CRA). Registering for your Business Number (BN) and CRA program accounts (GST/HST, payroll, corporate income tax, import/export) is the foundation of doing business legally in Canada.

This comprehensive 4-page Mackisen CPA guide explains when you need a BN, how to register using Business Registration Online (BRO), how to manage your CRA accounts, how to find an existing BN, and how CRA enforces compliance. Written in a high-authority accounting and tax blogger style with strong SEO, this guide is designed to educate business owners while positioning Mackisen as the trusted CPA partner for business setup, compliance, and strategic tax planning.

Legal and Regulatory Framework

Under the Income Tax Act and CRA administrative rules, all businesses carrying on activity in Canada must use a Business Number (BN)—a unique 9-digit identifier—to interact with the CRA and other federal programs. The BN is the “root” number for all CRA program accounts, including:

• RT — GST/HST account

• RP — Payroll deductions account

• RC — Corporate income tax account

• RM — Import/export account

• RZ — Information returns (slips and summaries)

The BN structure is:
123456789 RT 0001

Where:

• 123456789 = Business Number

• RT = Program type (GST/HST)

• 0001 = Program account identifier

CRA regulations require businesses to register before they start certain types of commercial activity, and to keep their BN and program accounts up to date.

Beginning November 3, 2025, CRA will no longer allow registration by phone—all registrations must be done through Business Registration Online (BRO), unless you use a representative such as Mackisen.

Key Court Decisions Affecting Business Registration

Courts consistently emphasize:

1. Commercial activity triggers BN obligations—even without formal incorporation.
   If you are earning income, you may need a BN and/or program accounts.

2. GST/HST and payroll obligations begin immediately upon reaching regulatory thresholds.
   CRA may retroactively assess tax if you fail to register on time.

3. Incorrect business structure does not excuse CRA non-compliance.
   Even hobby income can trigger registration requirements once it becomes commercial.

4. Corporations must update CRA when directors or addresses change.
   Failure to update can lead to invalid assessments or enforcement action.

5. Operating without a payroll account while paying employees is grounds for penalties.
   Employers are responsible for deductions and remittances whether or not the account is registered.

These rulings highlight why businesses must register properly and maintain active compliance.

Why CRA Targets Business Registration

CRA flags businesses for review when:

• Business income is reported without a BN

• GST/HST registration thresholds are crossed ($30,000 in 12 months)

• Payroll remittances are missing

• Corporate filings exist without BN linkage

• Sole proprietors operate under multiple trade names

• Import/export activity is detected without an RM account

• High-risk industries (construction, restaurants, trucking, online sales) fail to register

CRA’s matching systems detect unregistered commercial activity through:

• T4 and T5 reporting

• T5018 (construction industry reporting)

• GST/HST audits

• Credit card merchant account data

• Online platform reporting (e.g., Uber, Etsy, Amazon)

• Cross-border trade declarations

Business owners must register early to avoid penalties, reassessments, or frozen payments.

Mackisen Strategy

Mackisen CPA Montreal helps businesses:

• Determine which CRA accounts they need

• Register for BN, GST/HST, payroll, and other accounts

• Structure the right business type (sole prop, corporation, partnership)

• Complete business name registration

• Maintain accurate business information

• Add, modify, or close CRA program accounts

• Transition from unregistered to registered status

• Comply with GST/HST thresholds and payroll obligations

• Respond to CRA letters requesting registration

• Manage multiple business accounts under one BN

We ensure businesses avoid penalties, recover input tax credits, and maintain full CRA compliance from day one.

Real Client Experience

A self-employed consultant crossed the $30,000 GST/HST threshold but never registered. CRA reassessed two years of net tax, plus penalties. Mackisen filed a voluntary disclosure and reduced the exposure significantly.

A startup paid employees without a payroll account. CRA demanded CPP/EI back-payments. We opened the payroll account, corrected the filings, and advised on future compliance.

A non-resident e-commerce seller selling into Canada triggered GST/HST requirements. We obtained the BN and registered them for GST/HST and import/export accounts.

A corporation moved offices but didn’t update its BN. CRA sent compliance letters to the wrong address. Mackisen corrected the BN data and avoided an unnecessary audit.

These issues are common but preventable with expert guidance.

When You Need a Business Number (BN)

You must register for a BN when you:

• Incorporate a business

• Register for GST/HST

• Hire employees and need a payroll account

• Import/export goods (RM account)

• File T4, T4A, or other information returns

• Run a business that requires CRA remittances

• Operate as a sole proprietor with commercial activity

• Exceed the GST/HST small supplier threshold ($30,000 in 12 months)

Even if you remain under the threshold, you may still choose to register voluntarily to claim input tax credits (ITCs).

Register for a BN and Program Accounts

You can register through:

• Business Registration Online (BRO)

• Represent a Client, if you authorize Mackisen

• Provincial registries (Quebec, Ontario, etc.) that forward data to CRA

• Corporate registry when incorporating

Phone registration ends November 3, 2025.

Program accounts you may need include:

RT — GST/HST Account

Required when:

• You exceed $30,000 in revenue

• You voluntarily register

• You operate an online business

• You provide taxable services

RP — Payroll Deductions Account

Required when:

• You hire employees

• You pay yourself as an employee of your corporation

• You provide taxable benefits

• CRA reclassifies contractors as employees

RC — Corporate Tax Account

Automatically opened at incorporation.

RM — Import/Export Account

Required for:

• Cross-border goods

• Amazon FBA sellers

• E-commerce importing inventory

RZ — Information Returns

Required when filing:

• T4, T4A

• T5

• Other slip summaries

Ways to Find an Existing BN

If you’re unsure of your BN, you can:

• Log into My Business Account

• Contact CRA with business verification

• Search previous CRA correspondence

• Ask Mackisen to retrieve the BN through authorized access

Common reasons business owners lose track:

• Old dissolved corporations

• Multiple trade names

• Past accountants not sharing details

• BN linked to previous addresses

Mackisen helps recover, consolidate, or close outdated BN accounts.

Maintaining Your Business Information

Businesses must keep BN data accurate by updating CRA when:

• Changing legal address

• Changing directors or officers

• Adding or removing shareholders

• Changing bank accounts

• Closing a division

• Changing business structure (sole prop to corporation)

• Moving to another province

• ceasing commercial activity

Incorrect business information leads to:

• Misapplied payments

• Missed CRA deadlines

• Compliance flags

• Frozen refunds or GST/HST credits

Mackisen keeps your BN and CRA accounts aligned and up to date.

Common Questions

Do I need a BN as a sole proprietor?
Yes, if you need GST/HST, payroll, or import/export accounts.

Can one person have multiple BNs?
No—one BN per business entity, but multiple accounts under it.

Is GST/HST registration automatic when I get a BN?
No—you must register the RT account separately.

What if I never registered but earned business income?
You still must file business income; BN registration may be required retroactively.

Why Mackisen

With more than 35 years of combined CPA experience, Mackisen CPA Montreal helps entrepreneurs, contractors, corporations, and online sellers register their businesses correctly, maintain CRA compliance, and structure their operations for long-term success. We guide you through BN registration, GST/HST compliance, payroll setup, and account management—ensuring your business is protected from CRA penalties and fully prepared for growth.

If you want expert help registering your business, opening CRA program accounts, or navigating GST/HST and payroll requirements, Mackisen ensures you start right and stay compliant.