Every new Canadian business starts with a decision that most founders make almost by accident: what legal form the business will take. Whether you ever stop to think about it or not, the moment you start doing business you have adopted one of three structures — a sole proprietorship, a partnership, or a corporation — and each one is taxed differently, exposes you to a different level of personal liability, and sets you up differently for the day you eventually sell or wind the business down. There is no single answer that suits everyone, but understanding how the three structures actually work lets you make the decision deliberately rather than by default.
The sole proprietorship: the default for one person
A sole proprietorship is a business owned and run by one person. There are no partners and no shareholders, and it does not have to be registered to operate — it can simply run under the owner's own name. Bob Smith can fix your car and send an invoice that says "Bob Smith." If Bob wants a business name, he can register "Bob's Auto Repair," but registering a name does not create a separate legal entity. Whether registered or not, the business and Bob Smith are one and the same.
That identity between the owner and the business is the whole story of a proprietorship — both its appeal and its limitation. There is no separate tax return: the business has no T2 to file, because it is not a separate person in the eyes of the law. Instead, the owner reports the business income and expenses on their personal T1 return on a statement of business activities. If a sole proprietorship earned $128,000 and had $28,000 of expenses, the owner is personally taxed on the $100,000 of profit, and that amount lands on the T1 as taxable income.
The proprietorship is the quickest and least expensive structure to start and maintain. There are no annual corporate returns and no corporate-law formalities. But the same simplicity carries two real downsides. First, there is no liability shield: if the business is sued, it is Bob Smith who is sued, and Bob's personal assets are on the line. Second, all of the profit is taxed in the owner's hands in the year it is earned, whether or not the owner needs it. If the business earns more than the owner needs to live on, the surplus is taxed immediately at the owner's personal marginal rate — money the owner could otherwise have left inside a corporation to grow on a tax-deferred basis.
The partnership: the default for two or more
When two or more people carry on a business together with a view to profit, and they have not incorporated, they have formed a partnership — whether they intended to or not. The partnership shares most of the proprietorship's traits: it is quick to start, inexpensive to maintain, and there is no legal distinction between the business and the people behind it. Each partner reports their share of the income on their own return — a T1 if the partner is an individual, a T2 if the partner is a corporation — so all of the tax downsides of a proprietorship carry over to any individual partner.
A partnership adds one feature that deserves careful thought before you shake hands: each partner can bind the partnership. Any partner can buy, hire, and transact on behalf of the business, and if the partnership cannot satisfy the resulting liabilities, the partners are jointly and severally liable for its debts. That means a creditor can pursue any one partner for the whole obligation, regardless of who created it. A second concern is succession: unless a partnership agreement says otherwise, a general partnership between two people ends when one of them dies or leaves, and with more than two partners a death can leave a deceased partner with no interest to pass to a surviving spouse. A written partnership agreement, settled while everyone is still on good terms, is the way to manage both risks.
A limited partnership is a variation: one "general partner" carries the liabilities and runs the business, while one or more "limited partners" have limited liability and limited say in decisions. Unlike a general partnership, a limited partnership requires formal registration.
The corporation: a separate legal person
A corporation is fundamentally different from the other two structures because it is its own legal entity, separate from the people who own and run it. A corporation is owned by shareholders, who hold shares and usually vote at shareholder meetings; the shareholders elect a board of directors; and the directors appoint the officers — president, vice-president, treasurer — who manage the company day to day. The shareholders own it, the directors steer it, and the officers run it.
Because the corporation is a separate person, it creates a liability shield: shareholders and their personal assets are generally protected from the corporation's creditors and from lawsuits against the corporation. There are important exceptions — certain trust taxes such as unremitted GST/HST and payroll source deductions can pierce the shield and attach to the directors personally — but for ordinary commercial liabilities the shield holds. One caution: if a corporation pays dividends to a shareholder while it has unpaid taxes, the Canada Revenue Agency can treat that as a non-arm's-length transfer and claw the dividend back from the shareholder.
The tax advantages can be considerable. A corporation is taxed on its net income, and for a qualifying Canadian-controlled private corporation the small business deduction reduces the rate on active business income up to $500,000 a year to roughly 12.2% in Ontario. Take the earlier example: had the business incorporated and earned $100,000 after expenses, it could pay the owner the $66,000 they needed to live on and leave the remaining $34,000 inside the company. The portion of that surplus that would have gone straight to the Canada Revenue Agency at the owner's personal rate instead stays in the corporation, available to reinvest and grow. The tax is not avoided — it is paid later, when the money is eventually drawn out — but the deferral is real money working for the business in the meantime.
If you incorporate with more than one shareholder, a unanimous shareholders' agreement is close to essential. It governs what shareholders can and cannot do, sets out dispute-resolution mechanisms, fixes the votes needed for major decisions, and controls how shares can be transferred or pledged. It is far easier to negotiate while the founders are still friends than after a dispute has erupted.
A rough rule of thumb
No structure is right for everyone, but a useful starting point is this: if the business reliably generates more income each year than the owner needs to support themselves, a corporation is often the sensible choice for tax purposes, because the surplus can be retained and deferred. If there is no surplus at month-end, the corporation's tax advantage largely disappears, and the simplicity of a proprietorship may win. From a liability standpoint, though, a corporation is the stronger structure regardless — although good insurance can address many of the risks that a proprietorship leaves exposed. The right answer turns on your numbers, your risk profile, and your plans, which is exactly why the decision rewards a conversation rather than a coin flip. Our companion incorporation guide walks through what happens once you decide to incorporate.
How the work gets done
Choosing and setting up the right structure is part legal work and part tax planning, and the two have to be coordinated. Barrett Tax Law can help you weigh the structures against your actual numbers and goals, incorporate where that is the right call, and prepare the organizational documents — including a shareholders' agreement where there is more than one owner — so the structure is sound from day one. The first consultation focuses on your situation and the realistic options.
This guide draws on Dale Barrett's book, A Quick and Dirty Business Start-Up Guide. It is general information, not legal advice, and reading it does not create a lawyer-client relationship.