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Sector Rotation

Sector rotation is the movement of money between the 11 sectors of the stock market as the economic backdrop or investor sentiment changes. Investors do not sell stocks in general; they sell one group and buy another. Cyclical sectors such as technology and consumer discretionary tend to lead when growth and risk appetite are strong, while defensive sectors such as consumer staples, utilities and health care tend to hold up when investors want stability. Energy often moves with oil prices and inflation expectations. Because an index like the S&P 500 is weighted by company size, a rotation can leave the headline number almost unchanged while large moves happen underneath. A big drop in a heavily weighted sector can be cancelled out by gains elsewhere. That is why a flat index close does not mean a quiet market, and why breadth (how many stocks and sectors rise versus fall) is worth checking alongside the index level. Rotations are driven by changes in the things that hit sectors differently: interest rates, commodity prices, earnings expectations and shifts in the narrative around a theme such as AI. They can last days or years, and trying to time them is difficult. Many investors use sector weights to see how concentrated their exposure really is.