MAC addresses are typically assigned by the manufacturer of a network interface card (NIC) and are stored in either the hardware, the NIC read-only memory (ROM), or in the device firmware. A MAC address encodes the manufacturer's registered identification number (MAC prefix).
00-0C-29-20-99-07
is registered to VMware, Inc., USA90:DD:5D:C1:B2:A3
is registered Apple, USA