Lenders only sell more mortgages when they can make a decent return. And with Ginnie Mae looking to stem a decade-long decline in market share, the agency is hard at work finding ways to boost the cash flow it can offer originators. Ginnie Mae MBS “are pricing as well as they ever have,” said Michael Frenz, executive vice president at Ginnie and its interim chief executive. “We’re working with investors to provide more disclosures and…