“Paul Quintero is big on beginnings. He remembers the first loan his company made in 1991: $500 to a mother who’d lost her job at a factory in Brooklyn and wanted to start a Mexican food cart for her former co-workers. One cart became two, and two carts became a restaurant: Antojitos Mexicanos. When Quintero tracked down the owner in 2011, he learned she’d sold her restaurant, moved to Texas to start another business and put her kids through college.”