What unclaimed property actually is
Not a prize, not a lottery, not a lawsuit. It is your own money, sitting with a state because the company that owed it to you could not reach you.
How money ends up with a state
Every state requires businesses to hand over money they hold for someone they have lost contact with. The legal term is escheatment. Once it happens, the state holds the funds indefinitely and publishes the owner's name.
It is far more common than people expect, and it is rarely anybody's fault. An address changes. A company is acquired. A cheque goes to an old office. The business that owed the money has a legal deadline to hand it over, and it does.
What kinds of money
There is usually no deadline
In most states the money does not expire and it does not become the state's property. It simply waits. That is why balances reported decades ago are still claimable today.
It is also why businesses are the bigger opportunity. A company that has changed names, moved offices, absorbed a subsidiary, or been acquired often has several entries under names no one currently at the company would think to search for.