About this episode
Our Chief Cross-Asset Strategist Serena Tang discusses how rising oil prices and geopolitical tensions could make stocks and bonds move in the same direction, challenging one of the key principles of portfolio diversification.Read more insights from Morgan Stanley.----- Transcript -----Welcome to Thoughts on the Market. I’m Serena Tang, Morgan Stanley’s Chief Cross-Asset Strategist. Today: what happens if your main diversification strategy suddenly stops working because of oil price moves? It’s Tuesday, March 10th, at 10am in New York. For decades, investors have relied on the idea that stocks and bonds return tend to move in opposite directions. When equities fall, bonds often rise, helping cushion portfolio losses. But that relationship isn’t guaranteed. Between 2021 and 2023, coming out of the pandemic, stocks and bonds sold off together, and the traditional 60/40 equity-bond portfolio suffered its worst annual performance in nearly a century. Now, recent geopolitical tensions and rising oil prices are raising a familiar concern for investors: Could that uncertainty dynamic return? At first glance, oil prices may seem like a narrow commodity story. But in reality, they can shape the entire macroeconomic environment. The classic negative correlation between stocks and bonds depends on a fairly simple economic pattern: growth and inflation moving in the same direction. When economic growth accelerates, inflation often rises as well. In that environment, equities may perform well while bonds weaken. But when growth and inflation move in opposite directions, the relationship between stocks and bonds can flip. That’s what happened coming out of the pandemic. Bond investors worried about rising inflation, while equity investors were worried about slowing growth. In that scenario, both asset classes' returns declined at the same time.A sustained oil price shock could potentially recreate those conditions. Higher oil prices can push up inflation while also weighing on economic activity – a combination that economists often refer to as stagflation. If markets begin to price in that kind of environment again, the relationship between stocks and bonds could shift back toward that less favorable regime. Despite recent volatility tied to tensions in the Middle East, the relationship between stocks and bonds today still largely reflects the traditional pattern. Overall, stock-bond returns correlation remains negative, meaning bonds can still help diversify equity risk. In fact, correlations between U.S. stocks and 2-year Treasury returns have been trending negative since 2024, and on a longer-term basis they are now extremely negative relative to the past three years. But the key point here is that not all bonds behave the same way. M
