ARIN has been clamping down over the last 18 months or better to make sure that public IPv4 space isn’t misallocated, now that the supply is getting short.  In the early days, ISPs tossed out IPs like corn feed and now the chickens are coming home to roost.  So with the impending IPv6 rollout, what is happening?  Shady men with trenchcoats are pushing IPv4 space in dark alleys.

“Organizations slow to adopt IPv6 take heed: Surging requests for IPv4 addresses are quickly drying up the available store, raising the specter of an IPv4 black market that could dramatically increase the cost of obtaining a presence on today's Internet.”

Link here.