According to a new analysis from CLSA -- as reported by "AllThingsD" (http://macte.ch/FpE8i), there's little possibility of a decline in carrier subsidies for Apple’s iPhone at least not for the next 18 to 24 months. The research group thinks the structure of Apple’s carrier agreements will prevent this from occurring.

"We believe these are multiyear agreements which tend to stipulate subsidy policies up front," CLSA analyst Avi Silver says. "For the major carriers, we believe these agreements have most favored nation clauses so any offering from Apple to one carrier would have to be offered to the other. During the length of these multiyear agreements, we believe U.S. carriers would need permission from Apple to alter subsidy levels."

The CLSA analysis comes on the heel of a note from BTIG Research analyst Walter Piecyk to clients that he thinks Apple’s carrier partners are tired of offering such high subsidies on the iPhone.

"Subsidies by post-paid wireless operators have fueled the growth of Apple’s $600 iPhone since its inception," says Piecyk. "Wireless operators have been happy to subsidize smartphones to new and existing customers in order to provide a lift to the average monthly bill (ARPU) of their customer base, a metric which had been falling for the past three decades."