Learn how leadership shifts can change your portfolio and how sector rotation can help you respond.
By Saakshi Mehta, VP, ETF and Alternatives Strategy at BMO GAM
(Sponsor Blog)
Market commentary often reduces equity performance to a single question: are markets up or down? But equity markets do not move as a single block. They are made up of many industries, each responding to different economic forces and expectations around growth, risk and profitability. What looks calm at the index level can mask meaningful shifts beneath the surface.
Chart 1 introduces the Global Industry Classification Standard, or GICS, the framework most investors use to define equity sectors. By grouping companies based on their primary business activities, GICS provides a consistent structure for observing how leadership shifts across the market over time.
This is why sector rotation matters. Whether you actively rotate sectors or not, understanding sector exposures is essential for knowing what risks you’re taking and what’s driving your portfolio’s performance. Ignoring sectors can mean flying blind to some of the most important forces affecting your investments.
Sector rotation strategy is a valuable tool for individual investors seeking to enhance returns and manage risk, but it requires discipline, realistic expectations, and an understanding of both the opportunities and challenges involved.
Chart 1: Global Industry Classification Standard (GICS)
Source: MSCI, S&P Dow Jones, BMO GAM
The Core Concept
A sector rotation framework begins with the key observations: where leadership is forming, what forces are driving it, and how sustainable that leadership might be. In that sense, sector rotation is less about forecasting and more about interpreting what markets are already signaling.
The goal is to overweight sectors expected to outperform and underweight or avoid those likely to underperform. Capital tends to move toward areas where expectations are improving and away from areas where optimism has already peaked.
Sector rotation involves shifting your portfolio allocations among different market sectors based on where we are in the economic cycle. This matters because the performance gap between the best and worst sectors in any given year can exceed 15-20 percentage points (Chart 2). Being positioned in the right sectors can meaningfully improve your returns, while being stuck in lagging sectors can significantly hurt performance.
Chart 2: Sector Performance in the US in 2024 and 2025
Data as of year-end 2024 and 2025
Source: Bloomberg, BMO GAM
Divergence is a Feature, not a Bug
Sectors are influenced by different economic and structural forces. Interest rates, inflation, regulation, innovation, labour costs and commodity prices do not affect all businesses in the same way. Because these drivers rarely move in sync, sector performance naturally diverges.
That divergence is not a flaw. It is a defining feature of equity markets. It creates periods of concentration, periods of diversification, and conditions that allow leadership to rotate rather than remain fixed.
Market structure adds another layer. Sector composition varies significantly across regions. As Chart 3 shows, U.S. equity markets are heavily weighted toward Technology, while Canadian equity markets are dominated by Financials and resource-linked sectors. The same global environment can therefore produce very different outcomes depending on which market an investor is exposed to.








