Since his college days, Charles has developed an entrepreneurial streak. After working in his family's grocery business, he starts several ventures on his own. Even though Charles is independently wealthy, he is looking forward to working in each of the ventures. He plans to "drop in" on the businesses from time to time between personal trips to Europe and the Caribbean. As of the end of the year, he has established computer software stores in Dayton (Ohio), Austin, and Seattle; bagel bakeries in Albany, Athens (Georgia), and Tallahassee; and mountain bike and ski rental shops in small towns in Vermont, West Virginia, Colorado, and California. Identify the tax issues facing Charles.