Apple stock fell as much as 4 percent this morning as investors absorbed news of Steve Jobs’ latest leave of absence for medical reasons.

Apple said Monday in a statement that Jobs, the iconic chief executive of Apple was leaving again for an unspecified time on a medical leave. Chief operating officer Tim Cook is running the company’s day-to-day operations in the meantime. Jobs has taken leave for health reasons three times in the last several years.

The stock is currently at $337.43 a share, down $11.05 a share, or 3.17 percent. Apple will also be reporting earnings after the markets close today.

Analysts are expecting revenue to come in at $24.38 billion, up 55 percent from a year ago. Earnings per share are expected to be $5.38 a share, compared to Apple’s own guidance of $4.80 a share and revenue of $23 billion.

The analysts are expecting the number of iPhones sold in the quarter to hit around 15.6 million, with 17.75 million iPods sold, 4.08 Macs sold, and 6.15 iPads sold, according to Fortune magazine.

In August 2004, Jobs underwent surgery for a rare form of pancreatic cancer and returned to work after a month. In January 2009, Jobs took a six-month medical leave for what the public and Apple investors later learned was a liver transplant.