In another blow to troubled Canadian smartphone maker Research in Motion, energy drilling giant Halliburton Co. says it will replace its company-issued BlackBerrys with competitor Apple's iPhone.   

Halliburton said Tuesday it is making the move after deciding that Apple's technology works better with the programs it uses in the field. A spokeswoman for the firm says the plan will phase out 4,500 BlackBerrys from its operations.   

"We are making this transition in order to better support our mobile applications initiatives," said Tara Mullee Agard.   

"Halliburton has engaged with Apple on this transition, which is scheduled to take place over the next two years."   

BlackBerry developer Research In Motion has been struggling to keep a solid presence in the consumer market against Apple's products and other phones that use the Google Android operating system.   

However, an increasing amount of attention has turned to anecdotal accounts that RIM's longtime corporate clients are starting to explore a shift to other technology, such as the iPhone.

Corporate clients less fickle   

While the loss of any market share can be concerning to investors, the shift of corporate clients away from RIM is more troublesome because they are widely considered a reliable source of income.   

Unlike the fickle consumer market, which gravitates towards the latest trends, corporations tend to stay with the same technology for years.   

Halliburton, based in Houston, Texas and Dubai, is one of the largest energy drillers. It has operations in more than 70 countries, with about 70,000 employees.   

RIM has been under close scruntiny for the past year as its shares have eroded more than 75 per cent, with its most recent plunge coming after co-CEOs Jim Balsillie and Mike Lazaridis stepped down from their leadership positions.   

The shakeup followed a bad year that included 2,000 in layoffs, as well operational problems and public relations gaffes.

The Waterloo, Ont.-based company's stock closed up 12 cents at $16.65, or 0.7 per cent, on the Toronto Stock Exchange.