No, when you hold "bitcoins" with Coinbase, Coinbase just marks that down in their MongoDB database. You don't have a Bitcoin wallet on Coinbase at all. Coinbas

No, when you hold "bitcoins" with Coinbase, Coinbase just marks that down in their MongoDB database. You don't have a Bitcoin wallet on Coinbase at all. Coinbase has various wallets that they'll use in order to honour their MongoDB records of who they owe what.