Samsung

This is an easy one, isn’t it? For years, Samsung has been a thorn in Apple’s side, but as the company’s mobile shipments continue to grow, it’s becoming a real threat to Apple’s iPhone and iPad. Look for Samsung to continue to chip away at Apple’s mobile shipments in the coming years.

Google’s Android platform has thrown Apple into a jealous tizzy. The iPhone maker has removed Google’s YouTube app and Google Maps from iOS to prove it. Now Apple is mad at Google for launching new tablets and a smartphone that compete against its products. Apple can’t stand Google. It knows that every new mobile device that Google and its partners ship represents potential sales that could have gone to Apple.

Microsoft has always been a concern for Apple. However, that has mainly been about software. Now, though, Microsoft is working to attract more developers to its desktop and mobile operating systems. It recently started selling a tablet, and there are rumors that it might even introduce a Microsoft branded smartphone. Microsoft has its sights set on Apple.

This might come as a surprise, considering Motorola is not all that powerful in the mobile market, but it could actually cause trouble for Apple. After all, Google now owns Motorola. Although Google says it’s taking a hands-off approach to the mobile firm, you can bet it wants to make a profit on its $12.5 billion investment. The best way to do that is to take down Apple a peg or two.

Amazon is new to the hardware game, but it’s already made a splash. The company’s Kindle Fire tablets are extremely popular and some observers view them as among the best alternatives to Apple’s iPads. Couple that with prices that make Apple’s products seem awfully expensive, and it’s possible Amazon’s tablets take a bite out of Apple’s slate market share.

In the computing space, there’s really only one company that’s having some success increasing market share besides Apple: Lenovo. In fact, Lenovo is now the world’s largest PC maker. Based on its recent product announcement, Lenovo seems poised to gun for Apple both in laptops and tablets. Look for that fight to break out in 2013.

Although Sony is in some troubled waters at the moment, the company is still a home-entertainment juggernaut. Apple, meanwhile, is trying to make a run for the living room with products like its Apple TV set-top box. As Apple continues to expand in that space, look for the company to go head-to-head with Sony.

Carriers are deathly afraid of Apple. The iPhone is the world’s most popular smartphone, and people line up for days to get their hands on it. When most customers enter the store, they only want to look at Apple’s device. For carriers, that means less leverage and less ability to exert power and influence. Don’t think that doesn’t bother them.

Foxconn could eventually prove to be a company that that brings Apple’s growth to a halt. The company has been cited by the Fair Labor Association for inappropriate working conditions, and it seems that with each passing week, there’s another bad story coming out that’s linked in some way to the production of Apple products. Until Foxconn cleans up its act, the company is a liability for Apple.

Let’s not forget that Apple could prove to be its own worst enemy. Recently, CEO Tim Cook fired two top executives, Scott Forstall and John Browett, and modified his management structure to center power under a select few executives. That might prove beneficial. It might also prove troublesome. Considering that Apple’s vaunted secrecy seems to have gone by the wayside lately and its products are facing more innovative competition than ever, Apple could soon stumble over its own feet and find sales and profits in retreat.