Nortel Networks ;has sold 666,624 IPv4 addresses to Microsoft for $7.5m, according to Delaware bankruptcy court documents.
That's $11.25 per address, more than you'd expect to pay for a .com domain name. Remember, there's no intellectual property or traffic associated with these addresses -- they're just routing numbers.
Nortel contacted 80 companies about the sale a year ago, talked to 14 potential purchasers, and eventually received four bids for the full block and three bids for part of the portfolio.
Microsoft's bid was the highest.
The deal came as part of Nortel's liquidation under US bankruptcy law, which has been going on since 2009. According to a court filing:
Because of the limited supply of IPv4 addresses, there is currently an opportunity to realize value from marketing the Internet Numbers, which opportunity will diminish over time as IPv6 addresses are more widely adopted.
The total value of the entire IPv4 address space, if the price Microsoft is willing to pay is a good guide, is approximately $48.3 billion.
The Regional Internet Registries, which allocate IP addresses, don't typically view IP as an asset that can be bought and sold. There're processes being developed for assignees to return unused IPv4 to the free pool, for the good of the internet community.
But this kind of "black market" -- or "gray market" -- for IP addresses has been anticipated for some time. IPv4 is now scarce, there are costs and risks associated with upgrading to IPv6, and the two protocols are expected to co-exist for years or decades to come.