Apple Inc. (AAPL) - Get Apple Inc. (AAPL) Report stock has gained nearly 40% this year as the iconic device maker prepares to launch the 10th anniversary edition of the iPhone. 

Nevertheless, shares could go still higher following the highly anticipated debut of the iPhone 8 in Cupertino, Calif., next Tuesday, for a number of reasons that Bernstein analyst Toni Sacconaghi Jr. outlined in a Tuesday, Sept. 5, report.

First, Wall Street may be too conservative in its estimates of the phone's price and the number of devices that Apple will sell. 

"Press articles have widely speculated that the new, flagship iPhone 8 could start at $999+ vs the $769 for the iPhone 7 Plus today," Sacconaghi wrote. The projected price is "not entirely outlandish," he suggested, considering that Samsung Electronics Co. Ltd.'s (SSNLF) Galaxy Note 8 starts at $960.

For every $10 boost in the average selling price of iPhones, the earnings per share forecast for fiscal 2018 would rise 14 cents. If the iPhone 8 began at $999, the average selling price for the full line of iPhones in fiscal 2018 would be $750, or $50 above Sacconaghi's forecast. The boost would add up to 70 cents to the firm's earnings per share forecast.

Second, a look back at the stock's performance during the iPhone 6 sales boom also suggests the stock could move higher.

Apple "trades comfortably below its peak relative multiple during its last iPhone supercycle," Sacconaghi said.

Apple trades at 14.9 times forecast 2018 earnings per share, roughly the same multiple during the iPhone 6 cycle in 2014. The company, though, trades at a greater discount to the S&P 500 index today than it did in 2014. Adjusting for its discount to the S&P 500, Apple stock would be worth $186 -- versus its level of $161.66 on Wednesday morning.

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Third, exchange rates also could work in Apple's favor in 2018, the analyst said.

"Given our belief that nearly all of Apple's product costs are in [U.S. dollars], a 2-point benefit from currency could translate into $0.65-$0.70 in EPS," Sacconaghi wrote. 

Fourth, sales of Apple's HomePod in December could provide another lift. Apple's earnings per share would increase by 4 cents for every $1 billion in sales of the smart speaker, Sacconaghi estimated.

Fifth, the Apple Watch could boost earnings if healthcare providers subsidized the device and a connection to LTE wireless networks boosted demand. For each 3 million additional watch sales, Sacconaghi calculated, earnings per share would increase by 5 cents.

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Editors' pick: Originally published Sept. 6.