Last week, there were reports that United Microelectronics Corp (UMC) had won a contract with Qualcomm that would see them producing Snapdragon S4 chips. This would've been bad for TSMC, as it would be at their expense since they'd have lost the contract.
Considering TSMC is the world's largest contract chip-maker, they're losing contract to companies like Samsung and UMC. It looks as though Samsung is producing Qualcomm's Snapdragon S4 chips, using their 28nm manufacturing process.
It has been reported that Qualcomm's decision to switch from TSMC to Samsung isn't due to production quality, but quantity. Qualcomm doesn't seem to be confident with TSMC's ability to keep up with demand, but TSMC still believes that their 28nm manufacturing process is among the best. A TMSC spokesperson has chimed in with:
We do not comment on business with clients. We're confident in our leadership status in 28-nm and will fulfill customers' demands in the fourth quarter.