yeah their website does not give any information that people on this forum would like to see. But I have to say that for all of the negative criticism Castrol gets, they make a pretty decent conventional oil in GTX. Yeah their marketing BS leaves a bit to be desired, but there is no doubt they have some good chemists working for them who know something about oil. I am extremely impressed with their new 5w-20 conventional, sounds like a winner for anyone that wants to use that vis. I think Castrol does blend their own oil, I think that is all they do is blend, they purchase the base stocks from Shell or some other company, and then blend their own proprietary products. They are located around the world, so I guess it depends on how you look at them.