Historical clue formulations

• Stock unit: Abbr. — 2010-07-14
• Wall St. purchase — 2006-01-27
• Nasdaq unit: Abbr. — 2006-01-17
• Stock unit: Abbr. — 2003-02-23
• Nasdaq unit: Abbr. — 2001-11-18
• Amex unit: Abbr. — 2001-06-17