Related Clues:

• Company with a longtime travel guide
• Company once named Socony-Vacuum
• Exxon follower?
• Brand previously named the Socony-Vacuum Oil Company
• Producer of oils
• Exxon sister brand
• Gas brand with a red 'o' in its logo
• Exxon’s merger partner
• Alternative to Shell
• Competitor of Shell
• Gas giant?