A founder drafting a shareholder agreement for the first time starts with a blank page. An investor buying into a company that already has owners starts with whatever those owners already agreed to, disclosed or not, and the CBCA has a specific rule for exactly that situation.
Key takeaways
Most guidance on shareholder agreements is written for a group forming a company together, starting from nothing. An investor buying a minority stake in an existing business is doing something else entirely: inheriting whatever governance document already exists, or discovering there isn't one. The checklist for that situation runs in a different order.
s.146(3) answers the ownership question definitively: “a purchaser or transferee of shares subject to a unanimous shareholder agreement is deemed to be a party” to it. That happens automatically, by operation of the Act, whether or not the buyer ever saw the document or agreed to its terms. s.146(4) is the buyer's protection against being bound blind: where notice of the agreement was not given, the purchaser “may, no later than 30 days after they become aware of the existence of” it, rescind the transaction. That is a real, time-limited escape hatch, and it starts running the moment the buyer becomes aware — not the moment the purchase closed, which means a buyer who discovers the agreement six months after closing still has 30 days from that discovery, not from closing.
If an agreement exists, its exit and pricing mechanics were negotiated by the existing owners, on terms that may quietly favour them over anyone joining later. A book-value buy-sell formula that the founders were comfortable with when the company was young can be a poor deal for a new minority investor buying in at a higher valuation; see how differently the same company prices under different formulas before assuming the existing clause is neutral just because it predates you.
Absent a specific clause, a new minority shareholder gets exactly the same statutory floor as any other shareholder — s.21 records access and an annual s.155 financial statement, and nothing more. See information rights for a minority investor for what that floor does and does not cover, and confirm whether the existing agreement adds to it before assuming it does.
Check whether the existing agreement gives any shareholder a veto over major decisions, or whether the founders retained full board authority under the s.102(1) default with nothing restricting it. An investor buying a minority stake into a company where the founders can still issue new shares, take on debt, or approve related-party transactions without any consent requirement is buying a much more exposed position than the same stake with a negotiated reserved-matters list already in place.
Confirm the agreement addresses what happens if a founder stops contributing or becomes disabled after the investor has already bought in. Both of those scenarios change who the investor is in business with, and an agreement silent on either one leaves the investor exposed to exactly the kind of dispute those clauses exist to prevent.
It is worth being clear about a limit on all of this: CBCA s.21's records-access right belongs to existing shareholders and creditors, not to a prospective buyer who has not yet closed. See information rights for a minority investor for exactly where that right starts. Before closing, a buyer has no statutory tool forcing disclosure of an existing shareholder agreement, a valuation formula, or anything else — which is precisely why the request for a full copy of the corporate records, made a condition of closing itself, matters more here than in almost any other diligence category. Once the purchase closes, s.146(3) makes the buyer a party to whatever existed all along, disclosed or not; before closing, disclosure is voluntary, and asking for it in writing is the only real protection available.
Sometimes the answer to the first question is simply no — the company has multiple owners and no written agreement at all. Treadstone Law's baseline for what a first agreement should cover is a reasonable checklist to negotiate before closing rather than after: “how decisions are made”, what happens if a shareholder wants to sell, what happens “on death or disability of a shareholder”, and restrictions on competing with the corporation. Without an agreement, the OBCA's or CBCA's own default rules apply, and those defaults were not written with any particular group's actual intentions in mind.
Disclosed before closing, versus discovered after
An investor is offered 20% of an existing three-shareholder Ontario corporation.
The legal position is identical in both cases — the investor is bound as a deemed party either way — but only Scenario B gives the investor a live decision to make after the fact, and only because the agreement was not disclosed up front.
Yes. CBCA s.146(3) deems any purchaser or transferee of shares subject to a unanimous shareholder agreement to be a party to it, regardless of whether they negotiated its terms or even knew it existed at the time of purchase.
CBCA s.146(4) gives a purchaser who was not given notice of an existing agreement the right to rescind the transaction -- but only within 30 days after they become aware the agreement exists, so the clock starts running from discovery, not from the closing date.
It is worth checking what the existing formula would produce on current numbers before relying on it, since a formula the founders were comfortable with at an earlier stage of the business is not automatically a fair basis for pricing a new investor's entry or eventual exit.
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