That is a tough one if you don't know who the current owner of the business is. I'm not sure if this would have made news but you could try searching on the internet for your old company name to see if you can determine who bought it. As I understand it the old company is gone and you have no idea what the name of the new company is.

The other best option is if you know anyone that you worked with you can make contact with them personally to see if they know the name of the company.

Another option might be to call the city or better business bureau to see if they have historical records that may help you track the company's successor down.

If you get a company name we may be able to help you locate the plan but with no company name it is virtually impossible.

You could try your state's unclaimed property department, or the "missing money" website. (Beware: there's a lot of websites that want to charge you to search. MissingMoney is free.)