Hong Kong (CNN Business) Nissan CEO Hiroto Saikawa has resigned, dealing a new blow to the Japanese carmaker as it struggles to recover from the ousting of Carlos Ghosn last November.

The company's board of directors announced Saikawa's departure, which is effective September 16, after a meeting on Monday. It named Chief Operating Officer Yasuhiro Yamauchi as acting CEO while Nissan searches for a successor.

Saikawa's resignation came just days after he admitted to reporters in Japan that he and other top Nissan executives were overpaid as part of a stock-related payment plan. He denied any wrongdoing, and said he would return excess funds.

Nissan NSANY Theboard also revealed that an investigation found that alleged misconduct by former chairman Ghosn and Greg Kelly, a former Nissan director, cost the company billions in damages. It identified payments, some of which were deferred and never made, worth roughly 35 billion yen ($327 million). Nissan Board Chairman Yasushi Kimura said the company would not disclose further details because of ongoing judicial proceedings.

Details about the payments to Saikawa emerged in news reports ahead of Monday's board meeting. Speaking to reporters at a press conference in Japan on Monday, Kimura said the company's stock appreciation rights program, or SAR, was a subject of the probe triggered by Ghosn's surprise arrest.

Read More