California Demurrer — Legal Malpractice

Malpractice causation in transactional or litigation contexts requires the plaintiff to plead that they would have obtained a better result but for the attorney's negligence. In litigation malpractice, this is the "case within a case" requirement: the complaint must essentially plead a second lawsuit — the underlying action — and show that it would have succeeded absent the attorney's error.

If you're the moving party: Show that the complaint alleges "the attorney made an error" and "plaintiff suffered harm" without a causal chain. The typical gap: the complaint assumes the underlying claim would have succeeded without establishing the elements of the underlying claim and the evidence that would have supported it.

If you're the opposing party: In litigation malpractice cases, structure the complaint to allege the elements of the underlying cause of action (what plaintiff would have pled, what evidence would have supported it, what damages would have been recoverable) and then allege specifically how the attorney's conduct prevented that outcome. In transactional malpractice, allege the specific term that should have been negotiated and the specific transaction outcome that resulted from its absence.

Primary source: Viner v. Sweet (2003) 30 Cal.4th 1232, 1240-1241; Slovensky v. Friedman (2006) 142 Cal.App.4th 1518.

California Rules of Professional Conduct, Rule 1.4.2(b), requires an attorney to notify a client in writing at the commencement of representation if the attorney does not have professional liability insurance. Boyle Flats v. Hall held that a complaint alleging violation of this disclosure obligation states a cognizable rescission claim — the client who was not told the attorney lacked insurance entered the representation without material information relevant to the engagement decision.

If you're the moving party: Distinguish Boyle Flats on the facts (the client must plead not merely that no written disclosure was given, but that they were unaware of the lack of insurance and that this information would have been material to the engagement decision). A client who knew or suspected the attorney lacked insurance has no rescission claim even if the written disclosure was technically deficient.

If you're the opposing party: Plead the engagement timeline, the attorney's failure to provide written notice under Rule 1.4.2(b), and the client's lack of knowledge. Allege materiality: what the client would have done differently if informed (retained a different attorney, required the attorney to obtain insurance, or declined the representation). The rescission remedy requires the client to tender restoration of the attorney's benefit — address this in the prayer.

Primary source: Cal. Rules of Professional Conduct, Rule 1.4.2(b); Boyle Flats LLC v. Hall (LA Superior, Mosk Dept 34, May 7, 2026) — first-impression corpus signal. Rule 1.4.2(b) effective November 1, 2018.

A breach-of-fiduciary-duty claim against an attorney is not automatically separate from a professional negligence claim. Where the alleged breach is the same act or omission as the negligence claim and seeks the same damages, courts may sustain it as duplicative under the Careau principle.

If you're the moving party: Show that the fiduciary-duty count's operative facts and damages are coextensive with the negligence count. Where the only alleged fiduciary breach is a failure to exercise professional care — the same standard as negligence — a separate fiduciary claim adds nothing.

If you're the opposing party: Fiduciary duty claims survive when the attorney's conduct involved a conflict of interest, self-dealing, or undisclosed adverse interest that is distinct from simple professional error. A lawyer who had a financial interest in a transaction they advised on, or who represented conflicting parties, owes a fiduciary duty that goes beyond the professional negligence standard. Plead the conflict explicitly and distinguish the damages available (disgorgement, punitive damages) from those available in negligence.

Primary source: Slovensky v. Friedman (2006) 142 Cal.App.4th 1518, 1528; Stanley v. Richmond (1995) 35 Cal.App.4th 1070, 1086-1087.