Audi of America President Mark Del Rosso is stepping down after less than six months at the helm, the company announced today. Current Executive Vice President and Chief Operating Officer Cian O’Brien will fill the role on an interim basis. Neither Audi or Del Rosso have provided any specifics as to why Del Rosso is departing so suddenly, or whether it was his choice to step down. This is the third top executive change for Audi of America in seven years.

This change spells further trouble for Audi of America and continues a trend of executive and managerial changes that began in 2012. That was when the company lost Johan de Nysschen, the man largely responsible for the automaker’s years of success in the American market.

De Nysschen led the German automaker’s American arm to great sales and acclaim until May 2012, when he left to run Infiniti and, later, Cadillac. Scott Keogh followed de Nysschen and ran Audi of America until last December when Keogh was promoted to CEO of Volkswagen Group of America, with Del Rosso replacing him at Audi.

Now exactly 153 days later, Audi’s American arm is again without a formal leader. This kind of turnover at the top echelons is unheard of for a modern major manufacturer, and this news further darkens Audi’s U.S. prospects in the near term. Its new car designs have failed to receive the acclaim the automaker enjoyed in the early 2000s, the company has not enjoyed a record sales month since September of 2018, and this year’s sales are down 8.7 percent so far.

Del Rosso’s interim successor has been Audi of America’s COO since April 2017. It is unclear how long he will be required to fill the president role, or if he will eventually be handed the top spot formally. O’Brien has worked for more than two decades in the automotive industry. Before he was COO of Audi of America, O’Brien was head of sales operations for Audi UK, the German automaker’s fourth-largest market, starting in 2014. His experience at Audi UK, combined with his recent time overseeing America’s dealer network, should give him ample experience to try to turn around Audi’s recent fortunes in the U.S.