WhyItDropped

Nikkei 225 · April 30, 1970

The rumour that the world's biggest fund was going under

-8.69%

single-day change vs previous close

Part of a longer stretch

The 1970 squeeze in Tokyo

midway through · 1970-04-06 → 1970-05-27, -23.86% over the whole period

What happened that day?

  • The Nikkei fell 8.69% on the day, one of the largest single-session falls up to that point
  • The cause was a company called IOS, which ran what was then the world's largest investment fund and was rumoured to be in trouble
  • That fund held money across markets worldwide. If it failed, it would have to pull that money back, which meant selling — and the arithmetic moved before anything happened
  • Prices fell on **the expectation of selling**, not on selling itself. Sellers then called out more sellers
  • In Japan the episode was read as a sign that the longest postwar boom was ending. Years of rising profits and rising shares turned here
  • The following August the United States declared it would no longer exchange dollars for gold. The instability of the 1970s starts here

Sources

Every figure on this page is recomputed from the original daily closing prices and checked against them at build time. The account of what happened is written from the sources listed above.