How to Prove (or Defend) Aiding and Abetting Liability in California Tort Law

Introduction

Aiding and abetting is a civil liability theory in California that holds a person responsible if, with knowledge, they substantially assist or encourage another’s commission of a tort—even if they do not directly cause the harm themselves. This doctrine applies to both intentional and negligent torts, as well as to breaches of fiduciary duty. IIG Wireless, Inc. v. Yi, 22 Cal. App. 5th 630, 653–54 (Ct. App. 2018); Nasrawi v. Buck Consultants LLC, 231 Cal. App. 4th 328, 343 (Ct. App. 2014); Navarrete v. Meyer, 237 Cal. App. 4th 1276, 1290 (Ct. App. 2015).

Essential Elements of Aiding and Abetting Tort Liability

To establish civil aiding and abetting, a plaintiff must prove:

1. The defendant knew that the primary wrongdoer was committing or would commit a tort (such as assault, fraud, or breach of duty);

2. The defendant gave substantial assistance or encouragement to the wrongdoer; and

3. The defendant’s conduct was a substantial factor causing harm to the plaintiff.

Mere knowledge or passive inaction does not establish liability; there must be active participation or material support. American Master Lease LLC v. Idanta Partners, Ltd., 225 Cal. App. 4th 1451, 1476 (Ct. App. 2014); Casey v. U.S. Bank Nat. Assn., 127 Cal. App. 4th 1138, 1145–46 (Ct. App. 2005).

Distinguishing Civil Conspiracy from Aiding and Abetting

Aiding and abetting is distinct from civil conspiracy:

• Conspiracy requires an agreement to commit a wrongful act and makes all participants jointly liable for any damages caused.

• Aiding and abetting does not require an agreement; liability is based on knowingly providing substantial assistance or encouragement, regardless of participation in a plan.

  Stueve Bros. Farms, LLC v. Berger Kahn, 222 Cal. App. 4th 303, 324 (Ct. App. 2013).

Practical Guidance for Clients

• Plaintiffs should collect communications or documents demonstrating the defendant’s knowledge and active support, not just passive awareness.

• Defendants can defend by showing absence of knowledge, or that their acts were not a substantial factor in the harm.

• Specific intent to facilitate the primary tort is sometimes required and strengthens a plaintiff’s case.

Bottom Line

Aiding and abetting liability in California tort cases requires proof of knowledge, substantial assistance, and causation—without any need to show an agreement as in conspiracy. Only those who intentionally and significantly help a tortfeasor are liable under this doctrine.

Citations

IIG Wireless, Inc. v. Yi, 22 Cal. App. 5th 630 (Ct. App. 2018); Nasrawi v. Buck Consultants LLC, 231 Cal. App. 4th 328 (Ct. App. 2014); American Master Lease LLC v. Idanta Partners, Ltd., 225 Cal. App. 4th 1451 (Ct. App. 2014); Casey v. U.S. Bank Nat. Assn., 127 Cal. App. 4th 1138 (Ct. App. 2005); Navarrete v. Meyer, 237 Cal. App. 4th 1276 (Ct. App. 2015); Schulz v. Neovi Data Corp., 152 Cal. App. 4th 86 (Ct. App. 2007); Stueve Bros. Farms, LLC v. Berger Kahn, 222 Cal. App. 4th 303 (Ct. App. 2013).