Dow Jones Changes “Hoax” Index Divisor For First Time In 2 Years

For the first time in two years, the owners of the Dow Jones Industrial Average have changed the benchmark’s divisor, the number used to determine how moves in the share prices of individual Dow components affect the level of the index.

The new divisor is now 0.145233969 from 0.146021281. With the new divisor, a $1 price move in any Dow component will translate to a swing in the level of the Dow between 6.8854 and 6.8483 points.

MarketWatch reminds us, is a price-weighted index, which means its level is decided by the absolute price changes in its component shares, not percentage-point swings like other indexes.

Here’s a more in-depth explanation of how the divisor works, from MarketWatch.

“The so-called divisor, or in this case multiplier, is the figure used to determine the influence of any of the 30 components that make up the price-weighted Dow industrials.

The Dow isn’t exactly an average of its components, as its name might imply; instead, the value of the Dow is determined by calculating the sum of the prices of its components using a divisor that factors when a company splits its shares. Stock splits can swing the balance of influence for any one blue-chip component.”

The latest change in the divisor was made to accommodate the merger of Dow Chemical Corp. and DuPont Co., the latter of which is a Dow component. Shares of the new entity started trading Friday under the name DowDuPont, which is now a component of the blue-chip index. Before this, the most recent change came in December 2015 after Nike finished a 2-for-1 stock split.

S&P Dow Jones Indices said the change was meant to not “cause any disruption in the level of the index.” S&P Dow Jones Indices is a joint venture of S&P Global and CME Group.

Here’s a rundown of when previous divisor changes have occurred, courtesy of MarketWatch

Jan 1, 2002: 0.144521

June 3, 2002: 0.14445222

Aug. 21, 2002: 0.14418073

Nov. 19, 2002: 0.14585278

Feb. 18, 2003: 0.14279922

Aug. 20, 2003: 0.14249417

Sept. 30, 2003: 0.13500289

April 8, 2004: 0.14090166

June 6, 2004: 0.13561241

Nov. 15, 2004: 0.13532775

June 13, 2005: 0.13033708

July 14, 2005: 0.12560864

Oct. 3, 2005: 0.12493117

Nov. 20, 2006: 0.12482483

April 2, 2007: 0.123051408

June 13, 2007: 0.123017848

Feb. 19, 2008: 0.122834016

April 1, 2008: 0.122820114

Sept. 22, 2008: 0.125552709

June 8, 2009: 0.132319125

July 2, 2010: 0.132129493

Aug. 13, 2012: 0.12914682

Sept. 24, 2012: 0.130216081

Sept. 23, 2013: 0.155715905

March 19, 2015: 0.14985889

July 1, 2015: 0.149677273

Dec. 24, 2015: 0.146021281

Sept. 1, 2017: 0.145233969

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While the archaic index construction of The Dow never fail to fill us with folly, we are reminded of the detailed breakdown/explanation that Wim Grommen provided previously about the “hoax” of the Dow Jones Industrial Average…

The Dow Index was first published in 1896 when it consisted of just 12 constituents and was a simple price average index in which the sum total value of the shares of the 12 constituents were simply divided by 12. As such those shares with the highest prices had the greatest influence on the movements of the index as a whole. In 1916 the Dow 12 became the Dow 20 with four companies being removed from the original twelve and twelve new companies being added. In October, 1928 the Dow 20 became the Dow 30 but the calculation of the index was changed to be the sum of the value of the shares of the 30 constituents divided by what is known as the Dow Divisor.