Industrial AgeEconomy & Trade First bond ratings 1909Notable John Moody publishes letter grades for railroad bonds in his Analyses of Railroad Investments. Credit ratings become a gatekeeper of bond markets. ▲ MattersSaveShareTrace roots Longest chain: The Big Bang → First stars ignite → Supernovae seed heavy elements → The Sun forms → Earth forms → First oceans → First life → Photosynthesis evolves → Great Oxidation Event → Complex cells (eukaryotes) → Multicellular life → First animals → Cambrian Explosion → First vertebrates → Jawed fish → Fish walk onto land → The amniotic egg → The Great Dying → Dinosaurs appear → Asteroid ends the dinosaurs → Early primates → Apes split from monkeys → Human line splits from chimpanzees → Walking upright → First stone tools → Genus Homo appears → Homo erectus → Control of fire → Habitual fire and cooking → Homo sapiens appears → Complex language → Natufian villages → Oldest known bread → Agriculture begins → Irrigation → Uruk and the first cities → Cylinder seals → Writing (cuneiform) → Babylonian mathematics → Babylonian astronomical diaries → Thales and natural philosophy → Trial and death of Socrates → Plato's Academy → Aristotle's Lyceum → Alexander's conquests → Death of Alexander and the Hellenistic kingdoms → Seleucid Empire founded → Parthian Empire founded → Sasanian Empire → Birth of Muhammad → Muhammad's first revelations → The Hijra → Conquest of Mecca → Death of Muhammad and the Rashidun caliphate → Arab conquests → Abbasid Caliphate → Battle of Talas → Paper reaches the Islamic world → House of Wisdom → Al-Khwarizmi and algebra → Fibonacci's Liber Abaci → Bills of exchange → Medici Bank → Double-entry bookkeeping → Muscovy Company → English East India Company → Seven Years' War → Stamp Act → Boston Tea Party → American Revolution → Declaration of Independence → Articles of Confederation ratified → Shays' Rebellion → U.S. Constitution → The Federalist Papers → U.S. Constitution ratified → Washington inaugurated as first president → Hamilton's Report on Public Credit → Buttonwood Agreement → New York Stock Exchange organized → First bond ratings Community notesLoading notes… Learn more ranked by votesBookMichael LewisThe Big Short ↗Editor's pickVideoSearch on YouTubehistory of credit rating agencies ↗Editor's pick