Nissan Motor Co Chief Executive Hiroto Saikawa admitted to improperly receiving stock-related compensation .The admission raises more questions about Saikawa’s ability to steer Japan’s No. 2 automaker through a financial crisis in the wake of the arrest last year of former Chairman Carlos Ghosn, as mounting costs and sluggish sales sap profit.

“I thought that proper procedures were being taken,” he said, adding he had mistakenly believed his secretariat had dealt with it properly.

Saikawa told reporters he planned to return the payment. Sources told Reuters that an internal company probe found he had received tens of millions of yen more than he should have through a stock appreciation rights scheme.

The company’s investigation came after former Nissan director Greg Kelly went public with the allegations earlier this year. Saikawa is expected to share the results of the probe at a board meeting to be held soon, the Asahi newspaper said.

In an interview with magazine Bungei Shunju published in June, Kelly said Saikawa was granted an exception in 2013 to reschedule a stock-linked bonus that bumped up the payout by 47 million yen .

Confidence in Saikawa has already been shaken by accusations he was too close to ousted boss Ghosn, who, like Kelly, is awaiting trial on charges of financial misconduct. Both men have denied wrongdoing.