ComScore said it would appoint a chair and a lead independent director if needed, at the same time as finding a new CEO, which it is still searching for. Riley will serve as a consultant for the company until the end of the year.

Dale Fuller has joined its board of directors. He has extensive experience leading technology companies and is currently chairman of the board at MobiSocial.

Riley said: "Having completed the restatement process and set in place a number of initiatives that will enable the company to achieve its vast potential, I decided that now is the right time for me to step down."

The company is being investigated by the Securities and Exchange Commission (SEC) and in its restated financials it overstated revenue by more than $127 million from 2013 to 2015.

The company said the restated revenue involved how it valued several large transactions with WPP, with which it was in a 10-year strategic alliance.

Bill Livek, comScore’s executive vice-chairman and president said of the results: "The completion of our restatement process and the filing of current financials is an important step as it allows us to move forward and focus on delivering on the vast potential of our business.  We are significantly improving our accounting policies and procedures as we also constantly reinforce ethical compliance throughout our organisation."

Its latest financials show a net loss of $281m in 2017, on top of $117m loss in 2016 and $78m in 2015. ComScore has spent $130m on its investigation and audit to date.

Livek also said the company wants to regain listing on Nasdaq "as quickly as possible".