The Dow theory has been around for almost 100 years, yet even in today’s volatile and technology-driven markets, the basic components of Dow theory still remain valid. Developed by Charles Dow, refined by William Hamilton and articulated by Robert Rhea, the Dow theory addresses not only technical analysis and price action, but also market philosophy.
Charles Dow developed the Dow theory from his analysis of market price action in the late 19th century. And although he is credited with developing the Dow theory, it was S.A. Nelson and William Hamilton who later refined the theory into what it is today.
In 1932, Robert Rhea further refined the analysis of Dow and Hamilton in The Dow Theory
As with many investment theories, there is conflicting evidence in support and opposition of Dow Theory. The six basic tenets of Dow Theory as summarized by Hamilton and Rhea are described below.
1. Markets have three trends
Dow defined an uptrend (trend 1) as a time when successive rallies in a security price close at levels higher than those achieved in previous rallies and when lows occur at levels higher than previous lows. Downtrends (trend 2) occur when markets make lower lows and lower highs. It is this concept of Dow Theory that provides the basis of technical analysis’ definition of a price trend. Dow described what he saw as a recurring theme in the market: that prices would move sharply in one direction, recede briefly in the opposite direction, and then continue in their original direction (trend 3).
2. Trends have three phases
Dow Theory asserts that major market trends are composed of three phases: an accumulation phase, a public participation phase, and a distribution phase. The accumulation phase (phase 1) is when investors “in the know” are actively buying (selling) stock against the general opinion of the market. During this phase, the stock price does not change much because these investors are in the minority absorbing (releasing) stock that the market at large is supplying (demanding). Eventually, the market catches on to these astute investors and a rapid price change occurs (phase 2). This is when trend followers and other technically oriented investors participate. This phase continues until rampant speculation occurs. At this point, the astute investors begin to distribute their holdings to the market (phase 3).
3. The stock market discounts all news
Stock prices quickly incorporate new information as soon as it becomes available. Once news is released, stock prices will change to reflect this new information. On this point, Dow Theory agrees with one of the premises of the efficient market hypothesis.
4. Stock market averages must confirm each other
In Dow’s time, the US was a growing industrial power. The US had population centers but factories were scattered throughout the country. Factories had to ship their goods to market, usually by rail. Dow’s first stock averages were an index of industrial (manufacturing) companies and rail companies. To Dow, a bull market in industrials could not occur unless the railway average rallied as well, usually first. According to this logic, if manufacturers’ profits are rising, it follows that they are producing more. If they produce more, then they have to ship more goods to consumers. Hence, if an investor is looking for signs of health in manufacturers, he or she should look at the performance of the companies that ship the output of them to market, the railroads. The two averages should be moving in the same direction. When the performance of the averages diverge, it is a warning that change is in the air.
5. Trends are confirmed by volume
Dow believed that volume confirmed price trends. When prices move on low volume, there could be many different explanations why. An overly aggressive seller could be present for example. But when price movements are accompanied by high volume, Dow believed this represented the “true” market view. If many participants are active in a particular security, and the price moves significantly in one direction, Dow maintained that this was the direction in which the market anticipated continued movement. To him, it was a signal that a trend is developing.
6. Trends exist until definitive signals prove that they have ended
Dow believed that trends existed despite “market noise”. Markets might temporarily move in the direction opposite the trend, but they will soon resume the prior move. The trend should be given the benefit of the doubt during these reversals. Determining whether a reversal is the start of a new trend or a temporary movement in the current trend is not easy. Dow Theorists often disagree in this determination. Technical analysis tools attempt to clarify this but they can be interpreted differently by different investors.
The goal of Dow and Hamilton was to identify the primary trend and catch the big moves. They understood that the market was influenced by emotion and prone to over-reaction both up and down. With this in mind, they concentrated on identification and following: identify the trend and then follow the trend. The trend is in place until proved otherwise. That is when the trend will end, when it is proved otherwise.
Dow theory helps investors identify facts, not make assumptions or forecast. It can be dangerous when investors and traders begin to make assumptions off these facts. And while I find these types of analysis interesting, I’ll be sticking with my buy and hold index funds strategy.