Apple shares plummeted more than 5 per cent Wednesday after Cirrus Logic, a supplier of Apple components, slashed its own profit guidance, suggesting its Apple business had weakened. Apple shares were off US$22.33, or 5.2 per cent, to US$404.70 at 1830 GMT (2.30am, Singapore time) after briefly touching below US$400 a share earlier in the session. The drop came after Cirrus, which relies on Apple for a majority of its sales, warned on Tuesday that profits for its fiscal fourth-quarter, through March 30, would be lower. Cirrus reduced its revenue forecast and slashed its gross margin forecast after disclosing that it expects a US$23.3 million inventory reserve, of which US$20.7 billion is "due to a decreased forecast for a high volume product as the customer migrates to one of Cirrus Logic's newer components."