BlackBerry's new BB10 operating system is a clear improvement over previous iterations, but BlackBerry is still losing ground to competitors.

The Canadian company, previously known as Research in Motion (RIM), has just received another blow. After the Immigration and Customs Enforcement Agency decided last year to ditch the BlackBerry in favor of the iPhone, a big-box retailer has now decided to do the same.

According to an exclusive report from Apple Insider, Home Depot has supplied its executives with some 10,000 BlackBerry smartphones to date, but has now decided to switch to Apple's iPhone 4S.

Citing "people familiar with the big-box retailer's plans," Apple Insider reported that Home Depot has already started ditching the BlackBerry platform for Apple's iOS. Store managers and all corporate level employees will get new iPhone 4S handsets, eventually displacing roughly 10,000 BlackBerry smartphones.

"We are replacing our current base of BlackBerry technology with iPhones," a Home Depot representative told Apple Insider, noting that the move applies only to store managers, field ops and other corporate-level staffers.

Home Depot store employees are also using roughly 60,000 rugged Motorola smartphones (more than 34,000 so-called "first phones" and more than 25,000 "first phone juniors"), but the switch will not yet impact this segment. Motorola devices will reportedly remain in operation on retail store fronts for mobile point-of-sale (POS), walkie-talkie, analytical and traditional telephony purposes.

As of Q3 2012, Home Depot is the largest home improvement specialty retailer, operating roughly 2,252 retail stores across the U.S., Canada, China and Mexico. According to Apple Insider's sources, in the coming weeks, managers at those stores will receive iPhones instead of their current BlackBerry smartphones.

Home Depot is only the latest in a series of corporate and regulatory entities that decided to ditch the BlackBerry platform. Home Depot is the world's fifth-largest retailer, earning $947 million in profit on $18.13 billion in revenue in its latest reported quarter.

The BlackBerry platform was once the standard in mobile enterprise technology, but the company lost significant ground against rival platforms. When the U.S. Immigrations and Customs Enforcement agency dropped the BlackBerry platform, it spent $2.1 million on iPhones for its more than 17,600 employees. The National Transportation Safety Board and Australia's Treasury Department decided to ditch BlackBerry as well.