Business Insider understands the move had been planned for some time and a HSBC spokesperson told Adweek Clark is staying on to oversee the handover before a replacement is found.
His departure comes six months after Business Insider reported the bank laid off staff within its London-based global marketing department, including the marketer leading that division, Amanda Rendle. She had also been with HSBC for 15 years.
Separately this week, Reuters reported HSBC is set to cut "dozens" of jobs in its investment banking division.
Clark joined HSBC as its head of brand strategy in 2001 from