The first four tables show only the largest one-day changes between a given day's close and the close of the previous trading day, not the largest changes during the trading day (i.e. intraday changes).
Note that some sources (including the file Highlights/Lowlights of The Dow on the Dow Jones website) show a loss of −24.39% (from 71.42 to 54.00) on December 12, 1914, placing that day atop the list of largest percentage losses. The New York Stock Exchange reopened that day following a nearly four-and-a-half-month closure since July 30, 1914, and the Dow in fact rose several percent that day (from 71.42 to 74.56, or +4.4%). However, the apparent decline was due to a later 1916 revision of the Dow Jones Industrial Average, which retroactively adjusted the values following the closure but not those before, and it represents the only discontinuity in the index’s history rather than an actual loss.
This table shows the largest intraday point swings since 1987. As the "Net Change" column shows, 14 of these 20 largest intraday swings occurred during days in which the Dow declined, while only 6 occurred during days in which it advanced. All ten of the largest intraday swings have occurred amidst the ongoing global financial crisis, and none of the top 20 occurred before the year 2000. During the height of the crisis, nine of the ten largest intraday swings ever (and 14 of the top 20) occurred over a single span of trading days between September 29, 2008 and December 1, 2008.