The upcoming release of the next-generation iPhone from Apple is expected to have widespread implications for the global mobile market on a number of levels. Not only should it serve to increase the Cupertino, California-based company's smartphone platform and handset market share, but it will also affect mobile carriers, according to a recent comScore report.

For the first four years of its existence, the iPhone was only offered by AT&T and served to make the carrier one of the largest in the United States. Then, earlier this year, the highly anticipated move of the iPhone to Verizon Wireless was completed to give Big Red what it sought for so long.

Now, it appears that Sprint will also start offering the Apple device when the next-generation iPhone is finally released. That has been one of the many rumors circulating the internet in recent months, but is believed by many to be one of the more believable stories.

If true, that will leave only T-Mobile as the lone member of the top four carriers to not offer the iPhone. That point could prove moot once AT&T absorbs T-Mobile, barring further regulatory setbacks.

However the iPhone's stable of carriers shakes out, comScore concluded that it's not quite clear which will benefit most from Apple's latest offering.

Going into the company's press event to launch the device - slated for October 4 - AT&T still holds the lion's share of iPhone subscribers at 81.9 percent, according to comScore. That leaves Verizon with about 15.1 percent, the firm stated. Both could spike following the release of this week's iPhone, as both will almost certainly offer the older iPhones at a discount.

Then there's Sprint. The company can count on a portion of its current stable of subscribers to purchase the Apple device, but it remains to be seen if customers of other carriers will switch to Sprint. Working in the company's favor is the fact that it remains the lone carrier to offer a true unlimited data plan.

Apple is expected to put all the rumors surrounding the latest iPhone to rest at its upcoming press event. Also, industry experts believe the company will release more information on the latest version of the iOS mobile operating system and its cloud computing offering, iCloud. Not much has been heard about the latter since it was introduced earlier this year.