A sector represents a group of companies operating in similar industries or business activities, such as technology, healthcare, energy, or financials. Sector analysis helps investors understand industry-specific trends, regulatory impacts, and economic cycles that affect related companies. Sector rotation strategies involve shifting investments between sectors based on economic conditions.

Sector performance often moves in cycles based on economic phases, interest rates, and market sentiment. Understanding sector characteristics helps optimize portfolio allocation and identify investment themes. Sector-specific exchange-traded funds (ETFs) enable targeted exposure to particular industries without individual stock selection.

Real-world example: The energy sector outperforms during oil price rallies, with energy stocks rising 25% while the broader market gains only 8%, prompting investors to increase energy sector allocation through energy ETFs or individual oil company stocks.