Apple's status as the world's most valuable company makes any decline in its share price painful for the wider stock market.
Despite the 10pc drop over the last fortnight, the shares are still up just over 40pc this year after a run that prompted some Wall Street analysts to forecast that the shares will reach $1,000 (620 pounds) in 2013.
However, Apple chief executive Tim Cook faces a cluster of concerns that investors will be looking for some clarity on when the company releases its results after US stock markets close.
Verizon Wireless, America's second-largest mobile phone company, has said that it will start charging customers $30 to upgrade their phones, sparking fears that the telephone companies may start reducing the subsidies that have been vital to the success of the iPhone. Shareholders will also be eager to hear whether the new iPad, which went on sale in the US and the UK in March and a further 12 more countries last week, has been able to sustain its blistering start.
"The high expectations are the danger with investing in Apple right now," said Colin Gillis, an analyst at BGC Partners. "But the opportunity for the company is still big."
Apple is expected to deliver $9.4bn of profits in the first three months of the year, up from the $5.99bn it made in the same quarter in 2011. However, even if Apple matches expectations, profits will be far lower than the record $13bn it generated in the seasonally strong quarter running up to Christmas.