Introduction

In households where both spouses are incorporated professionals — two physicians, or a physician and a dentist, or any pairing of incorporated practitioners — the income planning picture is more complex than for a single-income incorporated household. The rules around income splitting, attribution, and TOSI apply differently when both spouses have their own professional income, and the opportunities available to this group are meaningfully different from those available to a single incorporated professional with a non-earning spouse.

The Attribution Rules: A Brief Overview

The income attribution rules in the Income Tax Act are designed to prevent taxpayers from shifting income to lower-income family members to take advantage of lower marginal tax rates. Where a taxpayer transfers or loans property to their spouse (or a minor child), income generated on that property is generally attributed back to the transferor and taxed at the transferor's rate.

For most professional couples where both spouses have substantial income, the attribution rules are less directly relevant — because neither spouse is significantly lower-income than the other. The issue is not attributing income from one spouse to the other; it is ensuring that each spouse's income is taxed correctly in their own hands.

TOSI and the "Excluded Business" Exception

The tax on split income (TOSI) rules, introduced and expanded in 2018, impose the highest marginal rate on certain types of income received by family members from a private corporation, unless an exception applies.

For dual-income professional couples, one of the most important exceptions is the "excluded business" exception. If a family member is actively engaged in the business on a regular, continuous, and substantial basis — generally interpreted as at least an average of 20 hours per week during the year, or in any five prior years — income received from the corporation is not subject to TOSI.

A physician spouse who works full-time in their own practice does not meet the 20-hour threshold for their spouse's corporation — because they are working in their own practice, not their spouse's. This means dividend income received by one physician spouse from the other physician's professional corporation may still be subject to TOSI, even though both spouses are high-income earners.

The exception for individuals aged 65 or older (where TOSI generally does not apply to share income) may become relevant for physician couples approaching retirement, but does not assist younger professionals.

Each Corporation as a Separate Planning Unit

For physician couples, each professional corporation is a distinct tax planning unit. The salary vs. dividend decision, RRSP contribution strategy, and compensation timing for each MPC should be planned independently — reflecting each physician's income level, personal tax position, and retirement goals — and then reviewed together to ensure the household picture is optimised.

For example, one physician may have significantly higher practice income than the other in a given year. The higher-income physician's corporation may be approaching the passive income threshold sooner; the other may have more capacity to accumulate retained earnings without that concern. These are separate planning conversations that benefit from being coordinated.

Shared Expenses and the Corporate/Personal Divide

Physician couples often share significant expenses — a home, vehicles, childcare, a vacation property. When each spouse has their own corporation, the question of which expenses are paid personally versus through which corporation requires some discipline.

Each corporation should only deduct expenses that are genuinely incurred for that corporation's business purposes. A shared vehicle, for example, should be allocated based on actual business use for each corporation — not arbitrarily claimed through one corporation for simplicity.

Estate Planning Dimensions

For physician couples with two incorporated structures, estate planning is more complex than for a single incorporated professional. Each corporation has its own share structure, retained earnings, and capital dividend account. Succession planning, life insurance arrangements, and the coordination of corporate and personal assets on death require a holistic review of both structures together.

When to Speak With a CPA

Physician couples with two professional corporations benefit most from annual planning that considers both structures together — not two separate, siloed conversations. A CPA who understands both household and corporate tax can identify coordination opportunities that individual-focused planning misses.

Rotaru CPA works with incorporated professional couples to plan compensation and structure across both corporations. Book a consultation to discuss your household planning.