What is the difference between a shareholder agreement and my company's articles?

Articles of incorporation and a shareholder agreement are two distinct and complementary documents that together govern an Ontario corporation.

The articles of incorporation are the constitutional document of the corporation itself. They are filed publicly with the Ontario government (or federally with Corporations Canada for a federal corporation) and set out the company's authorized share structure, any restrictions on share transfers in the articles themselves, and other fundamental features. Changes to the articles require a formal amendment process and shareholder approval.

A shareholder agreement, by contrast, is a private contract among the shareholders. It is not filed publicly, does not require government approval to change, and can cover detailed operational matters that would be impractical to embed in the articles. It can address things like voting arrangements, exit mechanisms, compensation, and dispute resolution.

The two documents must be consistent with each other — a shareholder agreement cannot override mandatory provisions of the Ontario Business Corporations Act. Where they overlap, the articles set out the company's public-facing structure, while the shareholder agreement governs the private arrangements among the owners. Both documents matter and should be drafted with each other in mind.