Shares of Apple stock briefly dipped below US$400 ($399.75, to be precise) on Wednesday. AAPL stock has traded just above $400 for most of the day, down more than 5% from its opening price of $420.60.

The stock is now trading at its lowest levels since 2011. Its market capitalization value has lost more than US$275 billion since late 2012.

As noted by “AppleInsider” (www.appleinsider.com), market watchers believe Apple’s slipping shares could be attributed to a warning of weak results that was issued by supplier Cirrus Logic. The company, which makes energy and audio chips, notified investors that it would see lower shipments of a high-volume product as an unnamed customer migrates to a newer component from Cirrus.