When beginning a business, you must decide what form of business entity to establish. Your form of business determines which income tax return form you have to file. The most common forms of business are the sole proprietorship, partnership, corporation, and S corporation. A limited liability company (LLC) is a business structure allowed by state statute. Legal and tax considerations enter into selecting a business structure. Sole proprietorships Partnerships Corporations S corporations Limited liability company (LLC) For additional information, refer to Small Business Administration's Choose a business structure webpage. Related Starting a business