Are slow iPhone sales just a blip or is Apple starting to struggle?

The volatile market in China, the urgency for a new product, and slumping phone sales are combining to create serious problems for the tech company

Self-made billionaire investor Carl Icahn is known for his very vocal endorsements and criticisms of the world's biggest public companies, including Apple. Yet when he appeared on CNBC on Thursday, he wasn't there to demand the company give shareholders dividends, as he'd been doing for years.

Instead, he said he was out. Icahn said he'd dumped every share he held in Apple, claiming he made a $2bn profit and was done with the company, citing concerns about how the Chinese government could block the company from that market. "You worry a little bit, and maybe more than a little, about China's attitude," Icahn said, warning of a "tsunami" of trouble.