(Bloomberg)—Luxottica Group SpA co-CEO Adil Mehboob-Khan resigned, becoming the third leader the maker of Ray-Ban glasses has lost in 15 months.

The stock dropped as much as 9%, also hurt by full-year sales that slightly missed estimates. The decline was the steepest since October 2014.

Luxottica’s e-commerce properties include SunglassHut.com, Ray-Ban.com and Oakley.com. Luxottica is No. 119 in the Internet Retailer 2015 Top 500 Guide.

Khan will leave at the end of February and be replaced by Luxottica’s 80-year-old founder Leonardo Del Vecchio, the company said after markets closed on Jan. 29. The departure of the former Procter & Gamble Co. executive adds to recent management turbulence, coming after the October 2014 resignation of CEO Enrico Cavatorta due to disagreements on corporate governance. Cavatorta had only been in the role for about a month, following the departure of Andrea Guerra after a decade at the helm.

“This will be greeted with some skepticism by investors,” Julian Easthope, an analyst at Barclays, wrote in a note. It’s likely that one of the company’s operational heads will take over after Del Vecchio has been in charge for two-to-three years, he said.

Khan’s departure was amicable, Luxottica said, adding that he will receive a payoff of about 7 million euros ($7.6 million).

Luxottica’s net sales amounted to 8.84 billion euros in 2015, trailing the 8.94 billion-euro average estimate in a Bloomberg survey. Growth was 4.3% at constant exhange rates, with the fourth quarter showing a 2% gain.