By Katie Marsal

Published: 08:30 PM EST

Shares of Apple Inc. were further battered and bruised on Tuesday evening, shedding over 11 percent of their value after the company guided considerably below Wall Street's expectations for its fiscal second quarter of the year.

The Cupertino-based Mac maker said it expects to earn $0.94 per share on sales of approximately $6.8 billion for the three-month period ending March, compared to Street consensus estimates of about $1.09 per share on nearly $7 billion in revenues.

The guidance sent shares tumbling to their lowest point in over four months -- down $17.35 or some 11.15 percent to $138.29 -- as investors feared that even a company with Apple's momentum may have trouble weathering a possible recession and sluggish global economy.

Shares had already closed down $5.72 or 3.54 percent to $155.64 earlier in the day.

During a conference call with analysts and members of the media, Apple chief executive Peter Oppenheimer defended his second-quarter estimates, calling it "very strong" guidance. "We are very confident we will achieve it," he said.

Also weighing on investor sentiment was word that iPod sales remained relatively flat in the US on a yearly basis, suggesting that the digital media player market -- which accounts for more than 40 percent of the company's revenues -- is quickly approaching its saturation point.

Apple executives immediately discounted the notion, however, noting that iPod revenues grew 17 percent year-over-year, a figure they maintain is "uncharacteristic of a saturated market."

Company officials further countered concerns by explaining that Apple hopes to transition the iPod touch -- the primary driver behind the iPod's 17 percent revenue growth -- beyond an advanced music player and into the first "mainstream Wi-Fi mobile platform" capable of running "all kinds of mobile applications."

Though executives failed to expand on this vision, the company is known to be working at least two initiatives that will help set it is handheld business apart from the pack even further. The first, due to arrive next month, is a software developers kit (SDK) that will enabled third parties to author a plethora of new applications for both the iPhone and iPod touch.

The second, as AppleInsider reported in September, is a slightly larger and much enhanced iPod touch-like device mostly reminiscent of a modern day incarnation of a Newton MessagePad -- the Apple handheld device that gave birth to the PDA market back in the 90's.