As a mining related company, buying Bitcoins from the market in order to pay out the dividends doesn't sound very plausible. However, I think in the case of receiving predominantly US dollars, the less hassle way for AM to do is to just keep the dollars for future use. As for long time investors, this might not be much of a problem (subjective opinion). Also, please note that, using Bitcoin as payment method has the advantage of being instant (relative to international wire transfers), and this advantage can be critical since chip buyers would normally expect their new ASICs to be shipped fast. Together with franchising, which generates Bitcoin revenue, we should be good.