The board of directors of US video game publisher Activision Blizzard said Thursday that there was no evidence to suggest that management had ignored or minimized accusations of sexual harassment. 

The firm behind hits like Candy Crush and Call of Duty, which Microsoft is acquiring in a blockbuster $69 billion deal, has been roiled by lawsuits and workers' allegations.   

Its CEO Bobby Kotick has apologized on behalf of the group and implemented a "zero tolerance" policy, while dozens of employees have been sanctioned or fired.

But according to the Wall Street Journal, the executive knew about reports of harassment for several years and sought to keep the incidents quiet.  

In a filing with US market regulators, the firm acknowledged Thursday the existence of cases of gender-based harassment.  

"The board and its external advisors have determined that there is no evidence to suggest that Activision Blizzard senior executives ever intentionally ignored or attempted to downplay the instances of gender harassment that occurred and were reported," the document said. 

The firm and its advisors have "not unearthed any evidence, directly or indirectly, suggesting any attempt by any senior executive or employee to conceal information from the board." 

Activision also hired Gilbert Casellas, a former chair of US discrimination watchdog Equal Employment Opportunity Commission (EEOC), for a review.  

According to the company, he concluded that there was no widespread harassment, recurring pattern or practices of harassment at Activision Blizzard or any of its subsidiaries. 

Still, the company reached an agreement last year with the EEOC to create an $18 million compensation fund for harassment victims.   

Activision also faces a case brought by California's rights watchdog, which launched a lawsuit last year alleging sexual harassment and discrimination at the company. 

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