Another avenue of attack might be getting copies of past tax returns. Many securities pay dividends which should have been claimed and reported - I know when I report mine that I have to notate who it was from, etc. - at least this would give you an idea of which specific securities or funds may be involved, which would in turn help you to identify the transfer agents in question (check his tax returns and look for all the forms called 1099-DIV attached, for starters - if he and mom filed jointly, mom should be able to get past copies from the IRS or tax professional).
I'm curious about this part:
What makes you think so? This may be an important aspect to nailing it down. Also, regarding this...I found out when I cashed in the first stock that there are others in my name as a minor with my mother or father as guardian.
Can we clarify that he WILL NOT give it...because of disclosure or other legal reasons related to the ownership of the account(s)....or he CANNOT give it because the account isn't held with him, or some other reason where there is no account or he doesn't have access to it, etc.? If the issue is that the transfer agent HAS the account, and it's only an issue of ACCESS to it, then it may be cleared up via the probate process of your father's estate (and again, may have implications if he and mom were BOTH listed). The custodian may just need the legaleese paperwork that says "the old account holder is gone, hail to the son, whom the court says is the new accountholder". What is the status of probate in regard to your father's estate?Only the stock transfer agent cannot give me the account number (even thought I'm listed on the stock) and without it, there's nothing I can do.

