Full disclosure: my portfolio is not concentrated in technology, but it does have outsized exposure to financials and real estate stocks, which I consider my core competencies. But most of the concentration principles still apply, and I have to keep them in mind. With real estate, they may look like different businesses (shopping malls, office buildings, apartment complexes, etc.), but they share the same macro sensitivity to interest rates. One test to see if you're too concentrated in tech or anything else is to ask yourself how much of your portfolio could fall on the same day, for the same specific reason, such as poor earnings from the hyperscalers. If the answer is an uncomfortable percentage, you might be too concentrated. – Matt Frankel, Team Hidden Gems