It's worth double checking the provision of your service agreement with the banker to ensure that s/he is no longer entitled to her/his fee. This is because intermediary service agreements typically have a tail. For example, it can say that if seller sells business within a certain amount of time such as 3 years after the termination of the service agreement to the same parties, the intermediary is owed its fee. And some service agreements can have a term of 1 year with auto-renewal. So net net, 1 year + 3 yr tail can mean your 4 year later situation today. If you don't owe a fee under your service agreement with the banker, then, yes, reach out directly. Hope this helps! (BTW, I'm also a lawyer so I have to say....this comment doesn't constitute a legal opinion and does not establish an attorney-cleint relationship between us.)

Review the NDA you signed first. Adhere to the terms in the agreement signed between you and the investment banker. If those terms haven't expired, go back to the investment banker. If they have expired, go directly to the FO. The FO has/had an agreement with the investment banker as well. Remind the FO they should review their agreement as they may or may not have commission due should you transact.