A disturbing feature of American taxes is the way some states tax the income of its residents earned both within and outside the state, as well as income earned within the state by nonresidents. Carly Fiorina, former Hewlett-Packard CEO and now presidential candidate, filed 17 state income tax returns last year. Many Americans file multiple state income tax returns in states where they do not live or work, but where they own a business or have income-producing activities. Ordinarily, the home state will allow residents a credit on income taxes paid to other states.