Historical clue formulations

• World's first billion-dollar corporation — 2026-02-15
• Eponym of Pittsburgh's tallest building — 2025-05-31
• Its N.Y.S.E. ticker symbol is "X" — 2019-04-18
• Pittsburgh-based N.Y.S.E. company — 2019-02-25
• Company whose headquarters were built from its own product — 2018-09-15
• Company that built the Unisphere for the 1964-65 New York World's Fair — 2015-03-03
• Co. with the longtime stock symbol "X" — 2014-04-13
• Pittsburgh giant — 2009-09-04
• J. P. Morgan co. — 2009-03-24
• Largest tenant of Pittsburgh's tallest skyscraper — 2008-04-04
• Andrew Carnegie corp. — 2007-07-23
• Pittsburgh giant — 2006-11-18
• Loser in a 1962 showdown with J.F.K. — 2005-09-03
• Corp. headquartered in Pittsburgh — 2005-02-26
• J. P. Morgan founded it — 1998-12-30