U.S. Cellular delayed the announcement of its first-quarter earnings to May 10 because of accounting errors the company recently discovered. The carrier, which is owned by Telephone and Data Systems, said the errors relate to accounting for sales tax liabilities and revenue deferrals. U.S. Cellular said the errors resulted in the overstatement of service revenues and understatement of sales tax liabilities from 2007 to 2009, and the related interim periods. The company said the errors had an "immaterial" impact on the affected periods. However, if the corrections were recorded in the first quarter, the company said the changes would have impacted first quarter results and comparisons to other periods. Release