The benchmark index that reached Japan’s 1989 stock-market peak before plunging was the Nikkei 225.
The Nikkei 225 is a price-weighted index of 225 leading companies listed on the Tokyo Stock Exchange’s Prime Market. It reached an all-time closing high of 38,915.87 on 29 December 1989, at the height of Japan’s asset-price bubble.
The index fell sharply after the bubble burst, reflecting declining share valuations and worsening expectations for the Japanese economy. Its later recovery took decades, which made the 1989 peak an enduring reference point in discussions of long-term market drawdowns.
The Nikkei is sometimes confused with TOPIX, another major Japanese equity index. TOPIX is broader and capitalization-weighted, whereas the Nikkei 225 is price-weighted and contains 225 selected constituents. The question concerns the index associated with the famous 1989 record peak.