> They would need access to the cold wallet on a regular basis if 97% of funds are truly in there.
Not true. First of all, that would only be true if their net daily turnover were more than 3% of their total amount stored -- which it may not be. Even then, I would expect graduated levels of cold wallets: imagine one with another 2% that is down the street in a bank safe deposit box, 5 wallets with 50% of the deposits stored in a way that can only be accessed with cooperation of 4 people in different parts of the country ... that sort of thing.
I am, of course, just speculating: I don't know how Coinbase runs their system, I just know that they seem competent and that this is how I would run such a thing.
Not true. First of all, that would only be true if their net daily turnover were more than 3% of their total amount stored -- which it may not be. Even then, I would expect graduated levels of cold wallets: imagine one with another 2% that is down the street in a bank safe deposit box, 5 wallets with 50% of the deposits stored in a way that can only be accessed with cooperation of 4 people in different parts of the country ... that sort of thing.
I am, of course, just speculating: I don't know how Coinbase runs their system, I just know that they seem competent and that this is how I would run such a thing.