US fastfood chain Burger King has said its chief executive, Brad Blum, has left the company after only 18 months in the job.

Blum is believed to have left due to strategic differences with the company’s board of directors, reported Reuters.

Burger King said it hopes to make a decision on a replacement for Blum by 1 August. Blum was the company’s ninth CEO in 15 years.

Under Blum’s reign, the fastfood company changed advertisement agencies and overhauled its menu, boosting US same-store sales.