A woman poses for a photo illustration with an iPhone as she plays Candy Crush in New York
A woman poses for a photo illustration with an iPhone as she plays Candy Crush in New York February 18, 2014. REUTERS/Carlo Allegri

Apple Inc shares are expected to get a boost from the release of the new iPhone anticipated to have a bigger screen. According to the latest edition of Barron's, Apple stock could increase by 20 per cent in 2015. The iPhone 6 is rumoured to be launched in the summer or fall.

According to Barron's, it is certain that Apple's latest iPhone will have a bigger screen compared to its 4-inch predecessors. A bigger-screen iPhone could attract new users and give iPhone owners incentive to upgrade to the latest iPhone.

Since the iPhone 5S hit the market in September 2013, Apple's flagship product still continues to enjoy solid sales despite several critics saying the iPhone 5S lacks innovation. The premium iPhone is in stores for six months now but sales remain steady as the iPhone is on track to become the most popular iPhone based on sales figures.

Aside from the iPhone 5S, the iPhone 5C is also doing well in the market despite receiving criticism for being the not-so-cheap iPhone. Some had even described Apple's iPhone 5C as a flop. According to a report by the Apple Insider, the iPhone 5C is the top 3 smartphone among U.S. carriers.

Apple Inc may have not priced the Iphone 5C right based on analysts' expectations, but the device itself is "not that bad." According to data, Apple Inc remains to be a dominant presence in the United States at the end of 2013.

The iPhone 5S was the number one smartphone across AT&T, Verizon, Sprint and T-Mobile in three months. Various reports have painted the iPhone 5C as a "terrible" product, but the cheaper iPhone beat Android flagships, including Blackberry and Windows Phone.

The ISI Group has upgraded Apple stock to a "strong-buy" rating as the firm has a $600 price objective on the stock. Apple investors may see significant gains in the company's stock in the next 12 months. According to Pacific Crest Securities analyst Andy Hargreaves, Apple stock could reach $635 with the impending release of iPhone 6 rumoured to have a bigger screen than the usual 4-inch iPhone.