three most important us refineries (marathon/valero/phillips66) vs wti/brent
interesting correlation since 2015 and fall in oil price due to last oil war (2014, opec vs shale)
the 3 companies refine half the daily barrels of the top 11 refineries in us
own more refineries than the next 8 companies of the top 11
according to date from january last year, dont know if they have changed since