Running a business rarely gives you a perfect moment to stop and look at the numbers. September, however, is a useful point in the year to do exactly that. There are still several months left to make adjustments, clean up records, review expenses and get a clearer picture of where the business is heading. At the same time, September 15 brings several federal tax dates that may apply to business owners and businesses. September 15 Is an Important Date for Some U.S. Businesses