Of the 3,700 Medicare certified freestanding ambulatory surgical centers in the United States, 2,600 (about 70 percent) are independent, 800 are in business with ASC corporate partners, 200 are joint ventured with hospitals and 100 are three-way joint ventures between physicians, an ASC company and a hospital. We'll briefly detail these four most common ASC business models so that you can decide which is best for you.