A data mix-up on a state tax portal inadvertently made private data from about 16,500 business taxpayers viewable to other companies, potentially even competitors. The breach lasted from Aug. 7, 2017, through Jan. 23, 2018. It allowed some companies to view other business’s names, federal employer identification numbers, tax payments, and other data. No individual employee information, such as Social Security numbers or wage data, was accessible to unauthorized people as a result.