The Ninth Circuit has determined that the loss to the victim as the result of a fraud-related conspiracy is the loss attributable to the entire conspiracy. That is because “all coconspirators are criminally liable for reasonably foreseeable overt acts committed by others in furtherance of the conspiracy they have joined, whether they were aware of them or not.” The court also determined that a sentencing enhancement based on loss to the victim was sufficient to prove the amount of loss, even in the absence of a restitution order.
The full text of Khalulyan v. Garland can be found here:
https://cdn.ca9.uscourts.gov/datastore/opinions/2023/03/30/21-70909.pdf