Rough estimates indicate just under 400,000 units sold so far.
Despite launching several months ago, Google's Nexus 4 smartphone is still pretty hard to find. The company's first device developed in collaboration with LG has suffered from supply problems from the beginning. Each time the phone becomes available on the Google Play Store, it sells out within a few minutes. Even those that do manage to snap one up are met with abnormally long wait times (as long as eight weeks) for delivery. So, the phone is in demand, that much we know. But how many has Google sold?
Neither Google nor LG has revealed any sales information, nor are they talking about production volumes. However, one user on the XDA Develops forums has used Nexus 4 serial numbers to estimate how many units have been produced since the phone was launched in October. User draugaz says that using the serial numbers to infer production rate indicates roughly 70,000 devices produced in October, 90,000 produced in November, and 210,000 produced in December. That equates to around 370,000 units since launch.
If this rough estimate is close to true, it seems LG and Google have ramped up production considerably since the October launch, producing triple the number of units in December compared to October. Still, the device remains sold out on Google Play, which means production still isn't where it needs to be to meet demand.