Bulk warehouse retailer Costco has added another item to its long list of consumer products: mortgages. Following a one-year pilot program, Costco of Issaquah, WA, has partnered with nearly a dozen mortgage lenders across the country to offer purchase and refinance loan products to the store’s U.S.-based members. The affinity marketing arrangement is not just pure marketing of mortgages but also aimed at ensuring that Costco’s members get the full value of their membership through high-quality service and savings, according to Jay Smith, the company’s director of marketing. Costco is no stranger to the...