Investing - Theory, News & General • VTI is now 41% technology — at what point does concentration become a diversification concern?

I was reading Vanguard’s latest semi-annual report for VTI and noticed that Technology was 41.0% of net assets as of June 30, 2026. VTI still holds 3,543 stocks, so obviously it is extremely diversified in terms of the number of companies owned.

What surprised me more was how quickly the technology weighting has increased:

2020: 26.2%
2021: 29.0%
2022: 23.4%
2023: 31.1%
2024: 35.1%
2025: 38.4%
June 30, 2026: 41.0%

So tech went from 23.4% at the end of 2022 to 41.0% today. Vanguard’s current report shows Technology as by far VTI’s largest sector, followed by Industrials at 12.5% and Consumer Discretionary at 12.3%.

I understand the standard Boglehead argument here: VTI isn’t making an active bet on technology. It is simply owning the U.S. market at market-cap weights. If technology companies become more valuable relative to the rest of the market, their weight in VTI should increase. That is part of the point of a cap-weighted total-market fund.

I'm also not trying to predict a tech crash, time the market, or argue that technology is necessarily overvalued.

But it did make me think about the distinction between diversification by number of holdings and diversification by economic exposure.

If 41% of a “total market” portfolio is now in one sector — and a meaningful portion of that is concentrated in a relatively small group of mega-cap companies — is it still reasonable to describe the portfolio as broadly diversified from a risk standpoint?

And, more importantly, if an investor is uncomfortable with that concentration, is there a Boglehead-consistent way to address it without simply making another active bet?

Some possibilities I’ve thought about:

Do nothing and accept VTI’s market weights.
Increase international exposure through VXUS, which would reduce overall U.S. tech concentration.
Add a value tilt.
Use an equal-weight index for part of the U.S. allocation.
Use a broad fundamentally weighted index.
Combine VTI with another broad index that has less mega-cap/technology exposure.

But this is where I get stuck:

If I deliberately underweight technology because I think 41% is too concentrated, haven’t I effectively decided that the market’s current weighting is wrong?

In other words, at what point does managing concentration risk stop being diversification and start becoming an active bet against the market?

For those who have been indexing for a long time, I’d be particularly interested in how you think about this.

Would VTI being 41% technology affect how you construct a portfolio today?

Would you simply let market capitalization determine the weights and ignore the sector percentages?

Or is there a level of sector/mega-cap concentration where you would intentionally diversify away from a pure U.S. cap-weighted total-market portfolio?

I’m not looking for a prediction about whether tech goes up or down next. I’m more interested in the portfolio-construction philosophy behind accepting versus mitigating this level of concentration.

Statistics: Posted by LearningTheCourse — Thu Aug 27, 2026 8:21 pm