I have 2 btc on Coinbase and send them to 2 separate addresses. How on earth can they know they are both mine without asking Coinbase? Seems fishy.
Discussion
Yeah it’s just BS guessing.
They will be “authoritative” with their calculations until someone calls them out on it then it will all be “an educated guess”.
I don’t even have the totals in one xpub. All from multiple sources.
…maybe they do have monthly chats with the exchanges!
I do not have and never would ever have 1₿ in one address or as 1 UTXO. Rich or poor, it's just so unlikely you would. Especially a pleb. Especially post 2017 when buying whole coins is not an option for 99% of people.
So... What they do is put together a made up methodology to estimate, then charge for the guess work with a straight face.
