Long-time Tesla Inc (TSLA.O) executive and president Jerome Guillen, who left the company earlier in June, has sold an estimated $274 million worth of shares after exercising stock options since June 10, according to a filing with the Securities and Exchange Commission (SEC).

The filing, which was submitted to the SEC on Tuesday, said that Guillen expected to sell 215,718 shares for $129 million that day, and that he offloaded another 145,289 stocks worth $89.6 million on June 14, and 90,111 stocks worth $55 million on June 10.

“It could raise some eyebrows for investors,” Wedbush Securities analyst Daniel Ives said, adding that investors are going to watch closely to see if he sells more.

Guillen, a former Mercedes engineer who was with Tesla since 2010, oversaw the company’s entire vehicles business before being named president of the Tesla Heavy Trucking unit in March. He left the company on June 3. read more

The departure of Guillen, one of Tesla’s top four leaders, including CEO Elon Musk, has sparked market concerns about Tesla’s future vehicle programs like the Semi electric trucks and new batteries called 4680 cells.

Stock options give employees and executives the right to buy their company’s stock at a specified price for a certain period of time. When share prices rise above the exercise price, they can buy the stocks at discounted prices.

It was not immediately known how much Guillen paid to exercise the options.