Complex sentence: Ulta, based in Bolingbrook, Illinois, is a chain of makeup and hair supply stores and Salons in the United States, which serves a market similar to that of Sephora.
Split into simpler sentences: Ulta, based in Bolingbrook, Illinois, is a chain of makeup and hair supply stores and Salons in the United States. Ulta serves a market similar to that of Sephora.