Compliance

Joint retainers: what has to be said before you act for both

September 5, 2026 · 5 min read

Acting for two clients on one matter is permitted and common. The Rules require specific disclosure first, consent recorded, and a decision made in advance about what happens if they disagree.

This article explains what published rules say and links to the original sources. It is not legal advice, and rules change. Your firm is responsible for its own compliance — check the linked sources for the current text.

Three things said at the start

Two spouses buying a house, two shareholders incorporating, a borrower and a lender on the same transaction. Acting for more than one client on one matter is routine, and chapter 3 of the Rules of Professional Conduct treats it as permitted and conditional rather than exceptional. The conditions are front-loaded.

Before accepting the retainer, each client is to be advised of three things: that the lawyer has been asked to act for both, that no information received from one can be treated as confidential from the other, and that if a conflict develops the lawyer may not be able to continue acting for either of them.

The second of those is the one clients least expect. Someone who tells their lawyer something in confidence, having assumed the ordinary rule applies, has been surprised at their own expense, and they were told otherwise at the outset only if somebody actually said it out loud.

What happens when they disagree, decided in advance

The Rules set a default and an exception, and the difference between them is a decision made at the beginning rather than at the moment of trouble.

The default: if a contentious issue arises between jointly retained clients, the lawyer is not to advise either of them on it and refers them out.
The exception: where the clients agreed at the outset that the lawyer could continue to advise one of them if a contentious issue arose, that agreement can be given effect, with the other client referred for independent advice.

The exception is only available if it was agreed at the start. It cannot be reached for once the disagreement has appeared, which is precisely when it would be most useful and least appropriate. Settling it in advance, while neither client has a position to protect, is the whole design.

Where this bites in practice

The joint retainers that go wrong are rarely the ones that looked risky. They are the routine ones: a couple whose purchase becomes a separation, two shareholders whose plans diverge, a private lender and borrower who are related and later are not on speaking terms.

In each case the file was opened while the parties agreed, which is exactly when the disclosure feels least necessary and is most cheaply given. A firm that treats the joint-retainer paragraph as a standard part of opening any multi-client file, rather than as a response to perceived risk, is the firm that has it when it matters.

Sources

Read on September 5, 2026. Each link goes to the original text, not a summary — check it for the current wording.

Rules of Professional Conduct, ch. 3 — Relationship to clients — conflicts, confidentiality, feesLaw Society of Ontario — Rules of Professional Conduct
Rules of Professional Conduct, r. 3.4-9 — Joint retainer — duty to advise of asymmetric-advice consequencesLaw Society of Ontario — Rules of Professional Conduct

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