[atyvr]

ARIN’s free pool of IPv4 address space was depleted on 24 September 2015. As a result, we no longer can fulfill requests for IPv4 addresses unless you meet certain policy requirements that reserved blocks of IPv4 addresses for special cases. https://www.arin.net/resources/guide/ipv4/ ie. you have virtually no other option than to buy on the private market

[j16sdiz]

ARIN is the first to deplete. I think other RIR still IPv4 left.