Unless the account located (supposedly) had some unusual form of co-ownership, the Order that you previously received after a full probate would be valid.
Pull order - it likely has % division of after discovered property, such as this.
You would likely not need to open a probate just for this.
The service that "discovered" the account, likely is clueless on the Order/Probate. You should contact them to discuss - likely non-issue (if there is an account).
But first - check controllers sites first yourself - maybe you can locate the account (s), no percentage fee! Did you pay this service already? You can check yourself.
I handled a probate in which there were $0 assets .. just claimed accounts at the Controller's Office (CA) which I recovered for the client - ZERO fee to outside service (just probate/attorney fees).
Decent amount of money at stake - don't sign a contract my recommendation, first do research/hire local attorney.
As indicated previously, the final orders issued in your parents' respective estates, should provide for the division of any later discovered property, and unless the Will(s) provided for the distribution of these specific assets (but they were missing at the time of the probate proceedings), the later discovered assets are part of the "residue" of the estate and the papers that you have should provide for how the assets should be divided.
That being said, some of the assets that are in the custody of the State Controller may have specific beneficiaries designated, and those designations could be controlling.
I would suggest that you check the State Controller's site (a link is included below) to see what you can find out. It would be a shame to pay the $18,000 to a service (that you don't have any experience with) if you could do it alone or with just a bit of aide from a local attorney.
There are many probate attorneys in Los Angeles that provide fee or low cost 30-60 minute consultations. So, if you don't already have an attorney, I would suggest that you (i) try to find the relevant assets on the State Controller's website, (ii) print out the pages that contain information about any assets that you find, and (iii) take those pages along with the order of final distribution you received at the end of your mother and father's probate, to a consultation with an experienced probate attorney in your area.
Any answer or other information posted above is general in nature and is not intended, nor should it be construed, as legal advice. This posting does not create an attorney-client relationship between you and the posting attorney, and you are urged to engage a qualified attorney who is licensed to practice in the relevant jurisdiction.
I've had some experience myself dealing with the Comptroller's office in Sacramento to release escheated property. It isn't easy, although at first it may appear as much. You are going to have to provide all of the back-up for the accounts (you're going to have to get that from the brokerage firm), a certified death certificate and most likely certified documents from the court where the estate was originally probated. The process from filing to a decision is 180 days. And you may have to go through that process at least twice.
These search firms that "find" unclaimed property are no substitute for good counsel, which will actually be cheaper and more apt to get the paperwork done right the first time.
For those looking for such funds for others, the link for each state's unclaimed property website may be found at www.naupa.org.
The foregoing is not legal advice nor is it in any manner whatsoever meant to create or impute an attorney/client relationship.
Most orders closing probates have a catchall phrase that permits the executor the power to find and distribute any after-acquired property. You may need to have a certified copy of letters testamentary re-issued. With the Letters, you should be able to apply for the funds, via the state controller's website. If you find it confusing, then use an attorney, who, at an hourly rate, will be able to wend his or her way through the thicket at a cheaper price than the company who contacted your sister.
I agree with everything that other counsel have said. An attorney should be able to help you (the four beneficiaires) collect this money without having to reopen probate and for much less than the 10% the company plans to charge.
The information you obtain at this site is not, nor is it intended to be, legal advice. You should consult an attorney for individual advice regarding your own situation.