Our Chief Global Cross-Asset Strategist explains why she sees a future for the 60/40 portfolio strategy, which worked well for over half a century and may continue to perform well – with some modifications.

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Welcome to Thoughts on the Market. I’m Serena Tang, Morgan Stanley’s Chief Cross-Asset Strategist. Along with my colleagues bringing you a variety of perspectives, today I’ll discuss the future of the 60/40 equity/bond portfolio.

 It’s Tuesday, July 16th, at 10am in New York.

Now investors have been asking: Is the 60/40 portfolio -- which allocates 60 percent to stocks and 40 percent to bonds -- dead? After all, the last two years saw some of the worst returns of this strategy in decades. Now, we think the concerns about this widely used strategy are not unfounded, but definitely a bit exaggerated. Exactly how one thinks about the right mix of equities and bonds within this type of portfolio though will need to change.

The strategy of investing 60 percent of a portfolio in equities and 40 percent in bonds to lower portfolio risk evolved from modern portfolio theory in the 1950s. To succeed, bonds must be less volatile than stocks and the correlation between stock and bond returns can't be 1 -- because that would mean a perfect positive correlation between stocks and bonds. And this correlation has been below 1 and low for a long time because growth and inflation have moved up and down in tandem for a long time. 

Now what does this have to do with anything, you may ask. Well, typically in an environment where equities are rallying on the back of strong growth, inflation is also increasing – which in turn means that nominal yields stay high, dampening bond returns; and vice-versa in a recessionary scenario. Now, in both of those cases, the negative stock-bond return correlations is related to the positive growth inflation correlation. Which explains why the strategy of the 60/40 equity/bond portfolio worked so well for decades, particularly in the low-vol, high-growth inflation correlation, low stock-bond returns correlation environment of the late aughts to 2010s. 

Unfortunately for investors though, this has not been the backdrop for the last few years. The highly unusual macro environment coming out of pandemic broke that relationship between growth and inflation, which in turn broke the relationship between stocks and bonds, led to a spike in fixed income volatility, and dragged bond returns to lowest levels in decades over the last couple of years. But we believe these factors will slowly normalize, which means 60/40-like strategies should work again. While the levels of correlation and bond volatility going forward may look different from history, and definitely different from the QE period, as long as bonds have lower risks than stocks – and there’s little to suggest they won’t – bonds will continue to be good diversifiers. 

But it’s important for investors to ask themselves: what could drive correlation between stocks and bonds going forward? Well, longer term, the path of correlation between the two assets depends in part on the relationship between economic growth and inflation, as I touched on earlier. And this is where AI can come in. Positive productivity shocks from GenAI tech diffusion and the energy transition may change that dynamic between growth and inflation. And at the same time, decoupling in the world’s key economic regions as a result of the transition to a multipolar world can alter the correlation between regional equities and rates. 

So, will the 60/40 portfolio be the strategy of the future? Or is it going to be more like 70/30 or even 50/50? Slower normalization of volatility and correlation means that a portfolio with more equity could yield better risk/reward than a 60/40 mix. On the other hand, as the world’s 65+ year-old population continues to grow over the next decades, this aging demographic may demand higher allocations to less volatile assets, even at the expense of lower returns. 

Or maybe, just maybe, there is another solution. Instead of a simple 60/40 like strategy, investors can look beyond government bonds to other diversifiers, and building a multi-asset portfolio with more flexibility. 

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