Understanding this indicator
A stock market can be viewed through countries or through the businesses that make up its economy. Sector indices offer the second perspective: they show how groups such as energy, manufacturing, financial services and utilities perform. This indicator draws their shared movement into a single line, helping reveal the broad equity cycle beneath changes in sector leadership.
Sectors respond differently to demand, costs and financing conditions, but many are exposed to the same economic environment. Improving orders can support several industries together, while tighter financing can affect businesses throughout the economy. Finding their common movement helps separate a broad market shift from a rally concentrated in a small number of industries.
The current sample uses US industry portfolios to observe equities by business activity. Their index levels are compared with a year earlier, adjusted for differences in trend and volatility, and combined using principal component analysis. The method identifies the strongest common pattern in the sample. It offers a sector-based view of the equity cycle, rather than a direct measure of industrial output or a census of every sector worldwide.
Compare this line with the cycle drawn from national equity indices. Similar movements show how the same equity environment appears through two different samples. Differences invite a closer look at sector composition and local conditions. For a fuller picture, pair the overall cycle with Sector Market Structure: one describes the common backdrop, while the other brings changes in relative sector performance into view.
The green line isolates the 3–4-year Kitchin cycle from the historical data; it is a fitted cycle, not a forecast of the next turn. The lower chart shows the 7–10-year Juglar cycle and the 15–25-year Kuznets cycle. Comparing these time scales can reveal why a shorter upswing sometimes sits within a much longer period of weakness. The two main-chart axes use different scales, so compare their timing and direction rather than the height of one line against the other. Historical curves may change as the data are updated.