It hasn't been an easy time for this sector but margin squeeze or no, our top five have powered on. Upstream operator BG Group comes first for the second year in a row, although it has to share this honour with Royal Dutch Shell, even though the latter posted third-quarter profits down by nearly a third to $4.5bn. Runner-up Tullow Oil is a BMAC stalwart, although this year it has shed three points. And recently listed Glencore Xstrata, which is suffering after a $7.7bn writedown on its mining assets meant it posted a net loss of $8.9bn in its first half, makes a first-time entry. BHP Billiton is back in the top 10 after two years away. And although BP has put the Deepwater Horizon calamity behind it, that wasn't enough to get it into the top five: it made only seventh place.