BP, SOCAR and partners have finalised the PSC extension for Azerbaijan's Azeri Chirag Guneshli (ACG) oil megaproject. As announced in December 2016, the current 2024 expiry date will be extended to end-2049. The international partners will pay a US$3.6 billion bonus and SOCAR (Azerbaijan's NOC) will increase its stake from 11.6% to 25.0%. The agreement will take effect upon ratification by Azerbaijan's Parliament. We evaluate the announced terms and five key takeaways from this landmark event.