If they are matching internally, they are doing so poorly if they can get them off exchange less expensively.
Maybe.Suppose their ability to send international wires in sufficient quantities was not scaling with their growth in BTC sales volume. In that case they'd have no choice but raise prices both to encourage more people to sell them bitcoins for USA, and to reduce the amount of BTC they have to source externally.
Right, that may well be. Which suggests a forward indication as they take about a week to award the coins bought there to the Coinbase cloud wallet, so not even transferable elsewhere.
