New Zealand experienced the largest one-day stock-market percentage loss during the 1987 global crash.
New Zealand’s stock market fell about 60 percent from its October 1987 peak through the crash period, making its decline far steeper than the famous losses in the United States and United Kingdom. The country’s market was relatively small and had been supported by a major financial and property boom, leaving it vulnerable when confidence collapsed.
The Dow Jones Industrial Average fell 22.6 percent on October 19, while London’s FTSE 100 lost 26.45 percent. Hong Kong’s market also suffered a severe fall and became an early signal of the international turmoil. These figures are often remembered more widely than New Zealand’s unusually large decline.
The crash’s effects in New Zealand contributed to a prolonged economic downturn and pressure for financial reform. Exact comparisons can vary depending on whether a source measures one session, a peak-to-trough fall, or a local calendar date, but New Zealand is widely identified as suffering the largest overall market decline associated with Black Monday.