To compute the sales factor, sales of services are attributable to California if a greater proportion of the income-producing activity is performed in California than in any other state, based upon the costs of performance. A taxpayer must include the activities of, and payments made to, agents and independent contractors who perform activities on behalf of the taxpayer when making its costs of performance analysis. However, assigning the location of the publishers’ income-producing activities is problematic in cyberspace.  The publishers’ income-producing activities occur across the country, and they do not indicate the state where the activities will be performed. They also do not indicate how much of the payments are associated with performance in what state, nor where the income-producing activities are performed. Therefore, the company activities must be assigned to the billing address of the customer by assuming that the customer’s activities are actively managed, directed, or controlled from the customers’ billing addresses.