Historical clue formulations

• Syndicate — 2019-02-10
• OPEC is one — 2013-07-16
• OPEC, e.g. — 2012-05-23
• OPEC, e.g. — 2008-05-27
• Trust — 2008-02-23
• Price fixer — 2005-03-06
• OPEC is one — 2004-02-17
• Trustbuster's concern — 2001-06-15
• Syndicate — 2000-12-10
• Price fixers — 1998-04-29
• Business combine — 1996-11-17
• Business group — 1995-03-24
• Business bloc — 1994-03-20