Shares of Apple Inc. (Nasdaq: AAPL) are sliding on the day that the iconic company unveiled its latest version of the wildly popular iPhone product.

As of 3:07 p.m. (New York time), the stock is down 4.75 percent to trade at $356.80 per share.

Apple shares had been mildly declining earlier in the session prior to new chief executive officer Tim Cook’s appearance at Cupertino, Cal. to showcase the new iPhone 4S model. By about 1:45 p.m. (EDT) shares started to tank.

 The less than stellar response may indicate some investors’ disappointment that the new iPhone may simply be a slightly upgraded version of the most recent model (iPhone 4), instead of a radically new device.

Moreover, since Sept. 20, 2011, Apple shares had already declined 9.4 percent before Tuesday’s trading session.

In addition, the absence of former chief executive (but ailing) Steve Jobs at the Cupertino shindig may also have left a sour taste in some traders’ mouths.

Colin Gillis, an analyst at BGC Partners, complained: It's been 16 months and all you've got is an A5 processor in the existing iPhone 4, according to Reuters.

Apple customers likely were not swept off their feet, which may be critical for the company since SmartPhones using Google’s Android platform already enjoys dominant global market share (43 percent versus Apple’s 28 percent, according to Nielsen).

The iPhone, which now represents more than 40 percent of Apple's revenues, will have to maintain its global momentum.