How high can Apple go?

When Apple Computer Inc. (AAPL) reports its second fiscal quarter results Wednesday, unless the iPod (search) and Mac maker soundly trounces analyst estimates, it could be hard for the stock to move higher, analysts said.

"With Apple good news already heavily discounted and in the stock, even the next new catalyst — namely Apple's earnings release on April 13 — might merely enable the stock to retrace its recent sell-off," wrote Goldman Sachs analyst Laura Conigliaro in a recent note to clients.

"Apple's recent performance suggests that it has become somewhat immune to positive earnings revisions and news flow at least for the time being," Conigliaro wrote, who last week raised her earnings estimate to 27 cents per share from 24 cents.

The last time the Cupertino, Calif.a-based company posted results, it blew past the highest Wall Street per-share analyst estimate by 7 cents and results were 11 cents higher than the consensus estimate of 24 cents.

Moreover, the company's results have topped average Wall Street expectations for at least the last seven quarters by progressively wider margins, according to Reuters Estimates data.

Already this week, some investors were stepping up their bullish expectations on Apple's stock options in anticipation of strong earnings.

"Even in a very difficult bearish stock market, options traders are accumulating bullish positions on Apple stock by buying calls ahead of its earnings tomorrow," said Jon Najarian, chief market strategist at PTI Securities, an online options, equity and futures broker based in Chicago.

Partly as a result of its success, current Wall Street estimates for Apple span a wide range of 21 cents to 30 cents earnings per share. The average analyst view is 24 cents on revenue of $3.18 billion in its second quarter according to Reuters Estimates.

Apple shares now trade at a price-to-earnings multiple of about 39 times fiscal 2005 earnings expectations. No. 1 PC maker Dell Inc. (DELL), long considered a technology growth stock, now trades at about 22 times its fiscal 2006 earnings expectations.

Notwithstanding the next, great gizmo from Co-founder and CEO Steve Jobs (search) and his crew of engineers at Apple, financial results could get a boost from the next version of its Mac OS X (search) operating system, code-named Tiger, which Apple said Tuesday will be available on April 29.

"We believe Mac OS X may also help spur an upgrade cycle for its core Mac business as Apple's installed base of around 25 million Macs and 'switchers' may be attracted to get Tiger for 'free' with a new Mac purchase," wrote American Technology Research analyst Shaw Wu in a note to clients.

At a cost of $129 and available at Apple's own retail stores, authorized Apple resellers and on Apple's online store, the upgrade is the fifth major refresh of Mac OS X and includes more than 200 features, including its Spotlight search technology, said Phil Schiller, Apple's head of worldwide marketing. Spotlight scours the Mac computer's hard disk drive to find documents, e-mails, pictures and music, similar to the way Google searches the Internet.

Some analysts believe that Tiger will help further distance Apple from Microsoft Corp.'s (MSFT) Windows XP in terms of Tiger's features, ease-of-use, stability and relative immunity to software viruses.

"Ironically, we believe Mac OS X Tiger may give a glimpse of what is in store for Microsoft 'Longhorn,' due to ship sometime in 2006," Wu wrote.

Shares of Apple rose 92 cents, or 2.2 percent, to $42.84 on Nasdaq. So far this year, the stock has climbed about 30 percent, after tripling in 2004.