One Position Is Growing Too Large
A position that started at 5% can silently become 15% through price appreciation alone. You never sold anything. You never deliberately added to it. But market moves shifted your allocation without you noticing.
Red flag: Any single position above 10%
Action: Check your top 10 holdings by weight. If any exceed 10% of total portfolio value, you have concentration risk.
One Sector Dominates
You own 12 different technology stocks and think you're diversified. You're not. You're concentrated in technology. When tech corrects 30%, your entire portfolio drops 20%+ regardless of how many individual names you hold.
Red flag: Any sector above 25%
Action: Calculate your sector weights. Technology, financials, and consumer discretionary are common concentration traps.
Your "Diversified" ETFs Overlap
Owning VOO, QQQ, and VGT looks like diversification. Underneath, you own Apple, Microsoft, and Nvidia three times over. The visible fund names hide dangerous single-stock concentration.
Red flag: Owning 3+ broad-market or sector ETFs
Action: Use an ETF overlap tool to see what you actually own. You may have 40%+ overlap between your "different" funds.
Your Broker View Hides Multi-Account Concentration
You hold 8% of company X in Fidelity, 7% in your IRA, and 6% in your old 401(k). Each account looks fine individually. Your total exposure is 21%, dangerously concentrated, but invisible across separate accounts.
Red flag: You don't have one consolidated view
Action: Aggregate all accounts into a single total. Multi-account holders almost always discover hidden concentration this way.
Next: Deep Dive into Concentration Risk
Once you've detected concentration, the next step is understanding how dangerous it is and what to do about it. Read the complete concentration risk guide to learn thresholds, real-world examples, and automated monitoring approaches.