Legal Question in Business Law in California

If you're merely acting as the collecting agent for client B, then client A is responsible for the result of his/her own negligence.

Client A as they caused the damage.

The obvious answer is that A pays for the damage. The issue that needs to be addressed is whether you did anything that would give B the reasonable impression that you were A's agent or A was yours.

Assuming that there was no written rental agreement, the "ostensible agency" issue focuses on whether you said or did something to create the agency. For example, did you connect yourself with A, as a family member, broker, attorney, or other relationship? Did you vouch for A's responsibility? Did you, in a conversation, assure B that A could be trusted...."I guaranty it."

Actions and slips of the tongue can create an agency, where the principal is liable for the agent's actions, even if the agency was unintended.

Look back at the transaction that led to your two clients entering into the rental agreement. See if there is something in that transaction that links you with A.

Good luck.