That's certainly a possibility. I was working from the assumption that Coinbase actually held BTC totaling the sum of all users account balances. Given the high

That's certainly a possibility. I was working from the assumption that Coinbase actually held BTC totaling the sum of all users account balances. Given the highly volatile nature of BTC and the nature of the BTC community (e.g. the conventional wisdom was to pull all funds from exchanges prior to the fork occurring), it seems quite irresponsible to not be holding funds as BTC. I'm aware that exchanges in the past have behaved very irresponsibly, but I'm hoping that Coinbase is the exception here as a well known US-based company.