ARIN announced a few days ago that the upper half of 50/8 now is delegated to Comcast. That is about 8 million addresses and is the largest delegation we have ever seen from a RIR.

It is unclear if this block will be used for customer equipment or just for internal devices. Comcast has previously announced that they are running out of the RFC1918 space and that they are using real IPv4 addresses for internal network devices.