The American Registry for Internet Numbers (ARIN) has announced the final exhaustion of their free pool of IPv4 addresses has reached zero. They are going to accept requests for IPv4, which will be approved via two ways: Join the waitlist for unmet requests in the hopes that a block of the desired size will be available in the future. If ARIN:receives any IPv4 address space from IANA (Internet Assigned Numbers Authority), or.recovers from cancellations, or.returns from organizations that have more than it needs.
Source: https://thehackernews.com/2015/09/ipv4-internet.html