With MBS issuance volume falling sharply in August, the mortgage industry may have another profit-related concern on its hands: gain-on-sale margins are coming under pressure. For now, no one is panicking, but until the recent rate drop – courtesy of China devaluing its currency – loan volumes were beginning to slow, especially for refinancings, although there’s plenty of hope that the purchase business will stay robust through the remainder of the fall. As one jumbo securitization official told Inside MBS & ABS: “Gain-on-sale margins have been...