A California nonbank is in the market with an excess servicing deal tied to an $11 billion Ginnie Mae portfolio, according to investment bankers familiar with the auction process. Sources contend the sale is being managed in part by Andrew Platt, a former managing director at MountainView Capital Group, Denver, a firm that’s an active broker of servicing rights. Platt now serves as vice chairman of Sprout Mortgage, a nonprime lender based in Henderson, NV. The deal is...