Manchester-based cyber security company NCC Group said Rob Cotton stepped down as chief executive and as an executive director of its board with immediate effect.
Brian Tenner, chief financial officer, will take over as interim chief executive and will lead the strategic review announced last week.
NCC said it expects to update the market no later than the company’s year end results due in July 2017.
Last month, shares of NCC fell more than 40% after it issued a surprise trading update, initiated a strategic review, and abruptly cancelled a capital markets day for investors.
Amid three profit warnings, NCC’s stock market value plummeted from more than £1 billion to roughly £300 million, according to Bloomberg data.
Analysts have speculated that NCC may now consider disposals, a breakup of the group or a full sale of the company.
In January, NCC said chairman Paul Mitchell would step down on May 31, 2017, and said three large unrelated contract cancellations in quick succession and one deferral in its assurance division had affected its rate of growth.
Mitchell said on Wednesday: “Rob has served the group for the last 17 years, steering it through its move to the London Stock Exchange’s main market in July 2007, following admission to AIM in July 2004.
“We would like to thank him for his major contribution and wish him well for the future.”
NCC said Debbie Hewitt, senior independent director, would continue to lead the search for a chairman to replace Mitchell.