2024-12-04
20 分钟A small number of stocks are driving most of the outsized gains in U.S. equities this year.
So is that a problem for investors?
I'm Allison Nathan and this is Goldman Sachs Exchanges.
Each month I speak with investors, policymakers,
and academics about the most pressing market moving issues for our top of mind report from Goldman Sachs Research.
This month I spoke to two prominent market watchers who are on opposite sides of this very relevant debate.
David Costin, our chief U.S. equity strategist in Goldman Sachs Research,
believes that investors should be concerned about the high level of U.S. equity market concentration today.
That's because he finds that high concentration is associated with lower returns over the longer run.
But Owen Lamont, senior vice president and portfolio manager at Acadian Asset Management disagrees.
He says that current concerns about high U.S. market concentration are overblown.
I started off by asking my colleague David Costin just how unusual the level of market concentration is today.
He discussed two measures he uses to determine this,
the share of total S&P 500 market cap accounted for by the top 10 stocks and the market cap of the largest stock relative to the 75th percentile stock.
One measure that's easy for people to comprehend, understand, track, follow,
what have you is the weight of the S&P 500 market cap that is contributed by the top 10 stocks.
We have data going back 45 years and we have data on a daily basis.
You can actually look at it very specifically.
The specific number is those top 10 companies today comprise around 36 percent of the market cap.
To go back over time, it's around 20 percent at the peak of the dot-com boom in 2000.