Client Event Recap · Markets & Discipline

Key takeaways from our conversation with Dimensional’s Marlena Lee, PhD

A few weeks ago, we had the pleasure of hosting Marlena Lee, PhD, Global Head of Investment Solutions at Dimensional Fund Advisors, for a conversation about what’s driving markets right now and how disciplined investors can think about it all. For those of you who couldn’t join us in person, here are the highlights.

The short version? Markets have been eventful, the headlines have been loud, and the case for staying diversified and disciplined is as strong as ever. Here’s what stood out.

Volatility Is the Price of Admission

Marlena opened by reminding us just how quickly markets can move. Anyone who got spooked and sold early in the year would have missed a sharp rebound over the following weeks. That’s the trouble with timing the market: you have to be right twice, and the strongest days often cluster right after the scariest ones.

Her bigger point was that volatility isn’t a malfunction—it’s the feature that makes long-term returns possible. The swings are the risk you’re compensated for. Drawing on roughly 100 years of data, she noted that equities have historically returned around 10% a year for investors willing to ride out the bumps. And those bumps are the norm: in only six of the past 99 years did annual returns actually land within two points of that 10% average.

The Market Is Looking Ahead, Not at Today’s Headlines

One of the most useful reframes of the evening: prices are forward-looking. By the time bad news dominates the headlines, the market has usually already priced in much of it. That’s why markets can rally precisely when the outlook feels grimmest—any outcome less terrible than feared can push them higher. She walked through the early COVID-19 crash as a vivid example: selling into the panic of early 2020 would have locked in losses right before one of the fastest recoveries on record.

Watch the Concentration

Marlena spent real time on the “Magnificent 7”—Alphabet, Amazon, Nvidia, Apple, Meta, Tesla, and Microsoft. There’s no question they’ve powered a huge share of recent gains, but that dominance cuts both ways. The 20 largest companies in the S&P 500 now account for nearly half the index’s value, so plenty of investors who feel well-diversified are quietly very overweight a handful of large U.S. tech names.

There’s a valuation wrinkle, too: those seven names occupy about 20% of a global allocation but contribute only around 13% of its earnings—a sign you’re paying a premium relative to the profits underneath.

The Case for Going Global

If concentration is the risk, diversification is the antidote. Nobody can reliably predict which region will lead next—so the smarter move is to hold them all. That point was well-timed: non-U.S. markets broadly outperformed the U.S. early in the year, with emerging markets up around 20% at one stage versus roughly 9% for the S&P 500.

Going beyond the S&P 500 into a globally diversified portfolio can mean holding more than 13,000 stocks, which dramatically reduces the chance that any single company or sector dictates your results.

On AI: Enthusiasm Without the Overreach

Marlena was measured on AI. Yes, it may bring real productivity gains, and yes, it’s lifted plenty of well-known tech names. But she was skeptical of chasing it through narrow thematic funds—many AI-focused ETFs haven’t actually beaten the broader tech sector or a diversified benchmark, and picking the individual winners and losers is a perilous game.

The dot-com era offers a sobering lesson here. The internet genuinely transformed the world, yet most of the top “internet” stocks of 1999 either underperformed for decades or disappeared entirely.

The reassuring flip side: if a technology truly permeates the economy, broadly diversified investors tend to capture its gains automatically. The big AI players are already core holdings in any standard global allocation—you don’t need a concentrated bet to participate.

A Few Things on the Horizon

IPOs. With some large offerings potentially coming—SpaceX among the most talked-about—Marlena offered a word of caution. In a typical IPO, only 3% to 5% of shares hit the public market at first; as insiders sell larger stakes over time, that growing supply can weigh on the price.

Inflation and stagflation. Inflation has been creeping up, and recession talk has grown. Marlena’s reminder: stocks can still post positive returns even when recession headlines arrive, because prices already reflect expectations. A balanced, patient portfolio has weathered a wide range of macroeconomic conditions.

The Bottom Line

Marlena closed where she began—on discipline. Yes, the long-term equity return has hovered around 10%, but earning it means accepting that any given year can look nothing like that average. 2020 was the perfect illustration: a brutal start, followed by a recovery that rewarded everyone who stayed put.

A disciplined investor looks beyond the concerns of today to the long-term growth potential of markets.

Her parting advice for navigating the noise was refreshingly simple:

• Stay diversified, across companies, sectors, and especially regions.
• Stay disciplined when the headlines get sensational.
• Work with advisors who put your interests first.

---