Apple shares have plunged after the company reported quarterly results that point to growth slowing after five fat years.
The stock was down 53.55 US dollars (£33.93) or 10%, at 460.46 dollars (£291.79) in midday trading.
Last night, Apple reported October-December earnings that were flat compared with the year before. Sales grew 18% from the year before, but the start-up of production lines for multiple new products like the iPhone 5 and iPad Mini held back profits.
Of more concern to investors is Apple sales growth forecast for the current quarter of around 7% - far from the 50-%-plus rate it's often hit in recent years.
Apple is usually cautious with its forecasts, but Chief Financial Officer Peter Oppenheimer indicated that it's moving toward providing more realistic figures from now on.
Analysts believe Apple is unable to fully capitalise on the global smartphone boom with just one new - and very expensive - phone model every year.
There has been speculation among company-watchers that Apple may launch a cheaper iPhone, or a premium model with a bigger screen, but CEO Tim Cook put a damper on those rumours in his comments on a conference call following the report.
Net income in the fiscal first quarter was 13.1 billion US dollars (£8.2 billion), or 13.81 US dollars (£8.70) per share.
Revenue was 54.5 billion US dollars (£34.4 billion), up 18% from a year ago. Analysts were expecting 55 billion US dollars (£34.7 billion).