Apple shares tumbled by US$50 billion on Friday, a sum bigger than the entire value of companies such as eBay or Ford.

The company released its latest line-up of products on September 12, including the iPhone X, iPhone 8, iPhone 8 Plus, Apple TV 4K, and Apple Watch Series 3.

The day before the launch, Apple had a market worth of US$834.9 billion but by the closing bell on Friday, its market value had fallen to about $782.5 billion. However the value of Apple is still about $100 billion bigger than Google-parent Alphabet.

Part of the reason for the share plunge appears to be problems with the latest Apple Watch whose new mobile phone technology simply does not work, according to journalists who have been testing the new devices.

Apple may also have been hit by fewer orders than expected for the forthcoming iPhoneX, which carries a record high price – as much as $1829 in Australia.

Gene Munster, an investor at Loup Ventures and a former top Apple analyst, had predicted a fall of up to 10 percent in Apple shares. He noted the stock had risen 50 percent in the past year, and said, “Naturally there’s going to be some people taking some profits.”