The ICANN Board has ratified the Global Policy Proposal for Post Exhaustion IPv4 Allocation Mechanisms by the IANA as sent by the Address Supporting Organization (ASO) Council to the ICANN Board on 13 March 2012. The proposal was posted for public comment from 14 March 2012 through 4 April 2012, during which time no comments were submitted. The Global Policy allows the Regional Internet Registries to return IPv4 address space to an IANA-managed pool from which equal parts will be allocated to all five RIRs in a deterministic manner on a regular schedule, once triggered.
http://www.icann.org/en/news/in-focus/global-addressing/allocation-ipv4-post-exhaustion. ICANN staff will be taking all necessary steps to implement the Global Policy.