Marissa Mayer Knew of Yahoo Breach Probe in July

Marissa Mayer has known since July that Yahoo was investigating allegations of a serious data breach, according to a person briefed on internal discussions, raising questions about whether the internet chief withheld information from investors, regulators and its acquirer Verizon until this week. Ms Mayer’s judgment in holding back information about the investigation is already being challenged. “If I were in Verizon’s boardroom I’d be very worried. You have to go back into every single assumption behind the valuation and redo it,” said Paul Heugh, chief executive of M&A consultancy Skarbek Associates. “Naturally such a breach will cause concern at board level for those involved in the M&A process and eventual purchase of Yahoo,” said Richard Cassidy, UK cyber security evangelist at Alert Logic, a security technology company. “Questions need to be answered on why external communication has been withheld for so long.”