Despite its seeming invincibility, even Apple AAPL +0.04% may struggle to climb the Great Firewall of China.

China is Apple's main growth market. In the quarter ended in December, China accounted for 13% of Apple's revenue, and Chief Executive Tim Cook has said he expects it will become Apple's largest market. Shareholders anxiously await a deal with China Mobile, 0941.HK +1.29% the world's largest wireless carrier by subscribers, to officially carry the iPhone.

Yet a string of criticisms and proposed regulatory curbs suggest Apple's trajectory in China may deviate from the cosmic course many expect.

The latest came in Wednesday's edition of the People's Daily. An article included Apple in a list of websites and app stores that have been investigated for providing pornographic content in China. This comes a month after Apple was attacked by China Central Television over its iPhone warranties, prompting an apology from Mr. Cook.

Then there is a proposed law that could give the Chinese government more control over apps and put new standards in place that may force companies to help the government track users.

David Fuller's view Aside from China uncertainties, Apple's success has inevitably inspired strong rivals. Moreover, some imperfections that investors would not have expected from Steve Jobs, starting with its maps when it dropped those from Google, has brought Apple's share price (historic, weekly & daily) back down to earth.

This is an opportunity for investors, now that Apple has retraced last year's blow off phase to the upside. However, there does not appear to be any urgency to buy the shares. Stale bull liquidation continues and is pressured by short sellers.

Nevertheless, Apple has returned to regions of previous support. It is not far off the 50% retracement level that may generate some additional interest. Tactically, for investors who commence nibbling on weakness, the secure dividend of 2.7% and rising as the share declines is a comfort during its underperformance. Alternatively, one can wait for evidence of Type-1, 2 or 3 base formation development, as taught at The Chart Seminar, although Apple will be well off its lows when the next base is clearly evident.