Mitsui & Co is buying a 20% stake in the Kaikias and Circius assets from Shell for an undisclosed sum. Kaikias will be Mitsui's sole asset in the deepwater Gulf of Mexico. Shell maintains an 80% interest and operatorship of both assets. Kaikias is a medium-sized, Subsalt Miocene oil field located near Shell's Mars and Ursa projects. We estimate reserves at 147 mmboe and a point-forward Brent breakeven of US$37/bbl, (NPV10). The project will be developed as a subsea tie-back with final investment decision (FID) expected in 2017 and first oil in 2019. Circius is an undrilled prospect in a neighbouring block.