How you respond to a FINRA written request for information can determine the outcome of the disclosure, so I recommend reading this article https://www.jdsupra.com/legalnews/i-received-a-finra-8210-letter-now-what-5734433/. Usually, smart securities experts, especially those with sales experience, try to talk their way out of a FINRA investigation. But investigations by securities regulators require experience and knowledge. Anything you say or information you provide to FINRA will be used to build a case against you.