I'm involved in two cases: MtGox and Grupeer. Neither were publicly traded companies that went bankrupt, but they're insolvency cases in general. In the former I had some play money (by now the coins owed might be worth thousands, but back then it was pennies) and didn't spend time figuring this out properly, in the latter I have a few thousand euros and collectively we (~2500 people) got ourselves a law firm in the relevant jurisdiction. With MtGox, at some point some step on the website didn't work (I felt like I kept having to reiterate that, yes, I still want my coins back) and it seems I now lost my claim or something, I don't quit get it. With Grupeer, I notice that we're on top of every development, filing disputes where necessary, and while I still spent multiple evenings reading through documents and collecting my data for evidence, we've totally got this.

If you ever find yourself with money in a bankruptcy and it is worth more than the lawyer's fee, definitely get a lawyer involved. They know what to file, to whom, when to take which step. The trustee or administrator is not going to come knocking on your door with your dues just like that.