One payment processor, Bitpay, has said they don't sell their coins on the open market. They have private buyers for them.
Bitpay partners with Bitwage, who provides Bitcoins to anyone receiving a paycheck via direct deposit. Simply setup your direct deposit to send a percentage to Bitwage's deposit account and you receive Bitcoins to your wallet address every pay cycle. No action is required to withdraw your Bitcoins. They are sent to your actual on-chain Bitcoin address immediately. It is essentially Bitcoin direct deposit. It circumvents hostile banks that might try to keep their customers from sending funds to Bitcoin exchanges. This allows for a complete cycle wherein Bitcoins spent at merchants who do not wish to keep them are then sent to Bitwage's customers rather than being converted to fiat currency at an exchange.