ARIN announced today that the transfer of IPv4 address space from the Nortel bankruptcy case was completed with Microsoft completing the “needs based” transfer requirement according to the existing ARIN policies.  Microsoft also signed a registration services agreement for this address space.

https://www.arin.net/about_us/media/releases/20110415.html

Court Approves Nortel’s Sale of IPv4 Addresses to Microsoft

IPv4 addresses no property Canada wieghs in on Nortel/Microsoft sale