What date marked the peak of Japan’s Nikkei 225 before the asset-price bubble burst?

Japan's Nikkei 225 reached its pre-burst peak on 29 December 1989.

The index closed at 38,915.87 on that date, marking the high point of Japan's late-1980s asset-price bubble. Share prices and urban land values had risen dramatically, supported by easy credit, optimistic expectations, and financial liberalization. The boom made Japanese equities among the world's most highly valued markets.

The Bank of Japan tightened monetary policy around the end of the decade. As credit conditions changed, land and share prices began to fall. The Nikkei declined sharply in 1990 and remained far below its 1989 peak for decades, while Japan entered a prolonged period of weak growth and financial stress.

The 29 December date is the market peak, not the day the entire economic adjustment ended. Japan's banking problems, falling collateral values, and bad loans continued through the 1990s. The episode is therefore usually called an asset-price bubble and its aftermath, rather than a single-day crash alone.