Dow Theory

Dow Theory is the set of principles drawn from Charles Dow's Wall Street Journal editorials and later organised by William Peter Hamilton and Robert Rhea. The averages discount information. The market has three trends, primary, secondary, and minor. A primary trend has three phases, accumulation or distribution, public participation, and excess. The industrial and transport averages should confirm each other. Volume should expand in the direction of the primary trend. A trend continues until a clear reversal signal. These are principles for the general market, built around two averages, not a candle-by-candle system. Modern "Dow Theory" newsletters add mechanical rules Dow did not write. Separate the principles from the product.

The practical remnant is confirmation and persistence. A high in one part of the market that is not matched by the economically related part is a warning, not a signal. A pullback inside a primary advance is a secondary reaction, not automatically a new bear market. The reversal, in the classical telling, required a failure of both averages to keep making highs, and then a break of a prior secondary low. Traders who invoke Dow to justify a one-bar reversal have left the theory. The theory was slow on purpose. It would rather be late than be whipsawed by the minor trend.

Use the principles as a checklist on index-level opinions. Is this move confirmed by a related market, or is it one index making a lonely high. Is volume expanding with the advance or drying up. Are you labelling a secondary reaction as a new primary trend because a week felt dramatic. The checklist will not time an entry. It will stop you from promoting every swing into a regime change. For entries, use the structure and level tools. For the regime, Dow's insistence that the trend is innocent until proven otherwise is still a useful default.

Quoting Dow Theory as a reason to buy a single stock. Also treating any divergence between two modern indexes as a classical non-confirmation. The original pair was industrials and transports, chosen for an economic story of production and shipment. A divergence between two overlapping cap-weighted indexes is a different, weaker fact. And claiming the theory calls tops. It was a trend-following logic. Tops were declared after the evidence, which is why critics called it late and supporters called it safe.

The economy Dow described is not the economy you trade. Services, software, and global supply chains do not split cleanly into the old average pair. Confirmation can stay broken for a long time in a bull market led by a narrow group. Volume is harder to read in a world of derivatives, dark pools, and all-day sessions. The principles are a lens. They are not a backtestable system until someone adds rules Dow left unspecified, and those rules are that person's system, not a recovered original.