While Sprint is increasing its WiMAX coverage in USA markets it appears that it has challenges to keep up with the sales of its first 4G HTC EVO handset. Sprint now offers 4G in 43 markets but does not have enough handsets to sell.

About 300,000 units of the EVO 4G have already sold since its early June release, and phone manufacturer HTC is having trouble keeping up with demand. HTC hasn't been able to keep up the demand.

EVO 4G is not HTC’s only problem, Verizon’s Droid Incredible is another one. The shortage of these handsets lies in the parts necessary to build the phone which HTC doesn’t produce itself, such as the touch screen.

For future devices, HTC has added more suppliers, recently signing a deal with Sony Corp. for screens for a new HTC phone.

This is not good news for Sprint as with in months Verizon is expected to join 4G train in USA market. Sprint needs to sort out supply issue without any further delay to maintain its 4G lead as it can cause big setback to it’s subscriber base.