The move does not mean that there are no IPv4 addresses left, but that requests will have to be smaller to be accommodated or applicants will have to wait for blocks of address space to be returned.

Source: IPv4 address stock dwindles as North American database runs dry – IT News from V3.co.uk

The dwindling amount of IPv4 addresses means that their worth is increasing, something the UK government is hoping to cash in on by selling off around 17 million unused addresses that could be worth millions of pounds.