Small Business Deduction 2024: $500K Limit, Associated Corporations, and Traps

Key takeaways

• The small business deduction (SBD) reduces the federal corporate tax rate from 15% to 9% on the first $500,000 of active business income for CCPCs
• The $500,000 limit is shared among all associated corporations
• Two tests reduce or eliminate the SBD: the taxable capital limit and the passive income (AAII) limit
• SBD income is taxed at roughly 12–13% combined federal-provincial in most provinces
• Investment income above $50,000 inside a CCPC reduces the $500,000 SBD limit dollar for dollar (multiplied by 5)

The small business deduction is the cornerstone of Canadian corporate tax planning for private companies. Understanding the limits — and the traps that reduce the limit — is essential for owners who run their businesses through corporations.

The $500,000 limit and associated corporations

Associated corporations must share the $500,000 SBD limit. If you own two corporations that are associated (because you control both, or a common person controls both, or cross-ownership thresholds are met), the combined active business income eligible for the SBD is still $500,000 — not $500,000 per corporation. The association rules are complex enough that a CPA review is warranted any time a new corporation is added to a group structure.

The taxable capital reduction

CCPCs with taxable capital employed in Canada between $10 million and $50 million face a reduction in the SBD limit. The SBD limit is reduced by $1 for every $10 of taxable capital above $10 million, phasing out entirely at $50 million. Taxable capital includes the corporation's capital (paid-up capital plus retained earnings plus long-term debt) less certain deductions. Most small businesses are well below $10 million.

Planning the SBD

Keeping active business income below $500,000 in high-rate years and accelerating income in lower-rate years can smooth the tax cost. Paying salaries to owner-managers reduces active business income. Deferring bonuses or accelerating them depending on the current year's income level are standard planning tools. The interaction with AAII passive income rules means that actively managing the investment portfolio inside a CCPC is now part of the SBD planning conversation.