Which 1989 event caused a sharp one-day US stock-market fall on Friday the 13th?

The 1989 event that caused a sharp one-day US stock-market fall on Friday the 13th was the Friday the 13th mini-crash.

On 13 October 1989, the Dow Jones Industrial Average fell 190.58 points, or 6.91%. The decline was associated with the collapse of a proposed leveraged buyout of United Airlines’ parent company, UAL Corporation, after financing failed.

The fall was much smaller than the 1987 Black Monday collapse, but it revived memories of that earlier crash and highlighted the dangers of leveraged transactions. Other markets also experienced turbulence, although the event did not develop into a repeat of 1987.

The episode is sometimes called the October 1989 mini-crash. Its name comes from the calendar date rather than from a particular long-term economic depression or a formal exchange designation.