The Nikkei 225's record closing level before Japan's bubble-era crash was 38,915.87.
The index reached that closing high on December 29, 1989, near the end of Japan’s asset-price bubble. Japanese share and land prices had risen sharply during the 1980s, supported by easy credit, optimistic expectations, and aggressive lending. The Nikkei’s peak became a symbol of the exuberance of that period.
After the peak, Japanese equities entered a prolonged decline. The Bank of Japan had tightened monetary policy, and falling property and share prices damaged banks, companies, and household balance sheets. Japan’s subsequent period of weak growth and financial stress is often called the Lost Decade, although economic difficulties extended beyond the 1990s.
The figure is a closing level, not the index’s intraday high. That distinction matters because financial indexes can briefly trade above a level before finishing the session lower.