The term is escheated to the state. I think you are holding a hoax after your ID information.

Bur, in that case it was the state that contacted me directly. There was no 3rd party taking a cut for tracking me down.

Contact the firm and make further inquiry?

The letter details their interest. They get about $75 for their work.
I still don't get why Coinbase would owe me anything.

They can enlighten you about that.

Good luck!

But, it's $475 of free money.
Certainly worth a phone call

The search firm is totally legit.
They have an 800 number, and the number search takes me right to their website link.
The letter also includes links to BBB, and a certification board for claimants' representatives.
I'm more & more thinking it's legitimate but I still don't understand why Coinbase would owe us money

https://icash.illinoistreasurer.gov/

This link is totally legitimate. My sister and I collected about $5,000 total last year in money owed to our mother from about 20 years ago. She received a letter from Mike Frerichs' office. It took a lot of documentation, including getting new copies of our birth certificates, and several months. We each ended up with a check for a bit under $2,500. It was a nice surprise, and I used it to buy a new bed.

I wouldn't necessarily trust Coinbase, but the state treasurer website is the real thing.

...with the Florida department of Consumer Services, Division of Licensing.
Leaning toward legit.
Still confused though. I'll call them tomorrow.