By Mathieu Rosemain and Laetitia Volga
PARIS (Reuters) - Shares in chipmaker STMicroelectronics slumped on Thursday, making them among the worst performers in Europe, on concerns that it could be late on supplying some components for Apple's next-generation smartphone.
STMicro shares were down by 5.6 percent in mid-session trading after French website iGeneration and DigiTimes reported that its 3D image sensors for Apple's next-generation handset - the iPhone 8 - may not be ready for a September debut.
A spokesman for STMicro declined to comment on the speculation.
STMicro was among the worst-performing shares on both the pan-European STOXX 600 index and Paris' SBF-120 market, although the stock remains up by around 30 percent since the start of 2017.
Apple is among the chipmaker's major clients, but the company does not provide details on the nature of components it manufactures for the phone-maker.
"According to a report by DigiTimes, there might be a lag of several months for the new iPhone's delivery," said Dorian Terral, an analyst for brokerage Bryan Garnier.
"It was the case for the iWatch, the MacBook Pro. It has nothing to do with the quality of (STMicro)'s products but rather with a longer-than-expected ramping up on Apple's side, because of the complexity of their phone," he added.
STMicro, Europe's third largest semiconductor company, announced in January a deal with an unnamed customer that can generate "substantial revenues" in the second half of the year, which analysts believe are tied to parts for upcoming Apple iPhones.
The next generation iPhone 8 line is expected to be released by Apple later in 2017.
(Reporting by Laetitia Volga and Mathieu Rosemain; Editing by Sudip Kar-Gupta)