Apple has lost its position as the world’s largest company after shares fell to a 18-month low with a 40 percent decline in stock prices from last September.

Shares closed at $23.44, a record low last seen in December 2011 a wiping out $20 billion in shareholder value, leading to Apple losing its leading position to energy giant Exxon Mobil.

The decline in share prices was influenced by a reduced sales forecast from one of the technology giants leading suppliers for its iPhone and iPad, suggesting a slowing demand for its flagship range.

Analysts are continuing to remain cautious, with fears that share prices may still have some way to fall.

Apple have struggled in recent months, particularly over the winter period, as the company faces increasing competition from rivals including Samsung and Google.

Expectations now rest on Apples line up of product releases in 2013 to turn around the companies decline.

Samsung overtakes Apple as leading manufacturer of ‘smart devices’