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Guide · Concentration risk

How much of your net worth should be in one stock?

If you work in tech or finance, a large slice of your wealth probably sits in one company's stock — RSUs, ESPP, options. It feels normal. It's also the single most common, most avoidable way people destroy a decade of savings. Here's how to think about it clearly.
Updated June 2026 · Informational only — not investment advice

Why concentration creeps up on you

Employer equity is designed to accumulate. RSUs vest on a schedule, ESPP buys every period, options pile up — and if the stock has done well, the position grows faster than everything else you own. Plenty of tech and finance employees wake up with 30%, 50%, even 70% of their net worth in a single ticker without ever deciding to take that bet. The bull market hides it; the drawdown reveals it.

The risk you're not being paid for

Markets reward you for taking systematic risk — the risk you can't diversify away. They do not reward you for idiosyncratic risk — the risk specific to one company, which you can diversify away for free. Holding 50% of your net worth in one stock loads you with a huge amount of risk the market won't pay you a premium to carry. You get the volatility of a single company without the risk premium that would compensate you for carrying it.

The double-whammy for employees: your paycheck and your savings depend on the same company. If it stumbles badly, you can lose your income and your nest egg at the same moment — exactly when you can least afford it. Enron and Lehman employees learned this the hard way.

The math of a big drawdown

Concentration amplifies both tails, but losses hurt asymmetrically. A position that falls 50% needs to double just to get back to even. A single great company can absolutely deliver — but it can also fall 60–90% on a thesis break (plenty of former darlings have), and a concentrated holder has no cushion when it does. The question isn't “is this a good company?” It's “can my financial life survive if I'm wrong about this one company?”

Common rules of thumb

There's no universal number, but a few heuristics financial planners use a lot (general guidance, not advice for your situation):

  • The 10–15% ceiling: many advisors get uncomfortable when any single position exceeds ~10–15% of investable net worth.
  • The “buy it again” test: if you had the cash today, would you buy this much of this one stock? If not, you're holding it out of inertia (or tax fear), not conviction.
  • The sleep test: if a 50% overnight drop would change your retirement, your house, or your job security, the position is too big regardless of how good the company is.

What to actually do about it

Diversifying a concentrated position is as much a tax and timing problem as an investing one, so the point isn't “sell everything.” A sane framework:

  • 1. Know the real risk first. Read the actual fundamentals — balance-sheet strength, earnings quality, whether the price already assumes perfection. The point isn't to time the market; it's to know whether your one bet is quietly deteriorating.
  • 2. Understand vesting & tax before you sell. RSUs are taxed as income at vest; selling appreciated shares triggers capital gains. A qualified tax advisor earns their fee here.
  • 3. Diversify systematically, not emotionally. A pre-set schedule (or a 10b5-1 plan if you're an insider) trims the position on autopilot, so you're not trying to pick the top.
  • 4. Monitor the fundamentals, not just the price. The dangerous deterioration — rising leverage, falling cash conversion, a restatement, an auditor change — shows up in the filings first, often well before the price reacts.
Stockonomy was built for exactly this holder. Run your concentrated position through the forensic engine to see its quality grade, red flags, and distress screens from the filings — and add it to your watchlist so you get a plain-English heads-up when a new SEC filing materially changes the risk. You don't want to be the last to know about the one stock that matters most to you.
Read the real risk in your concentrated position

Grade, red flags and distress screens from the filings — free, no card. Then watch it for changes.

Analyze any US filer — free →

Stockonomy is an educational research tool. Nothing here is investment advice, a recommendation, or a solicitation to buy or sell any security. Forensic signals flag probability, not certainty. Data is sourced from public SEC EDGAR filings.