# Concentrated Stock Positions: The Risk Hiding in Your Best Winner

Source: https://cluenex.com/learn/portfolio-management/concentrated-stock-position/
Publisher: Cluenex (https://cluenex.com)
Updated: 2026-10-15

## Short answer

A concentrated stock position is a single holding large enough that its decline would materially change your financial plan. There is no fixed percentage, but J.P. Morgan found 44% of Russell 3000 companies from 1980 to 2020 suffered a 70% peak-to-trough loss that was never recovered.

## Key takeaways

- A concentrated stock position is one holding large enough that its decline would change your financial plan. It usually arises from appreciation, not a decision, so it is rarely noticed until it is large.
- Catastrophic single-stock losses are common. J.P. Morgan found 44% of companies in the Russell 3000 between 1980 and 2020 fell 70% from peak and never recovered.
- Company quality is not a safeguard. In J.P. Morgan's 2024 update, 54% of catastrophic decliners were profitable at their peak and 63% carried net debt-to-EBITDA of 2x or less.
- Recovery math is lopsided: a 50% loss needs a 100% gain to break even, and a 70% loss needs 233%. Near retirement, the scarce resource is time.
- Tax is a reason to phase a sale across years, not a reason to keep the exposure. Set the target weight first, then choose the schedule.

## What is a concentrated stock position?

A **concentrated stock position** is a single holding that makes up enough of your total wealth that a decline in that one security would materially change your financial plan. There is no universal percentage, because the threshold depends on what the money is for.

A 40% position in a portfolio that must fund a retirement starting in four years is concentrated. The same 40% in money you will never need to spend is closer to a preference.

The defining feature is how it arises. Almost no one deliberately puts 60% of their net worth in one company. The weight is the arithmetic result of one holding growing faster than everything else you own.

The exposure grows without a decision being made, and the track record that produced it is exactly what makes trimming feel unnecessary.

## How often do single stocks fail?

More often than most people expect. J.P. Morgan Private Bank's *Agony & Ecstasy* research uses the Russell 3000, a broad index of the US market, and defines a **catastrophic loss** as a decline of 70% or more from peak that is never recovered.

| Russell 3000 companies, 1980 to 2020 | Share of companies |
|---|---|
| Suffered a catastrophic loss (70% from peak, unrecovered) | 44% |
| Delivered negative absolute lifetime returns | 42% |
| Underperformed the Russell 3000 over their lifetime | 66% |
| Were "megawinners" (500% or more cumulative return versus the index) | 10% |

The rate differs by sector. Information Technology companies suffered catastrophic losses at 54%, Utilities at 16%. Owning one stock means accepting the failure rate of its sector, not the market average.

Hendrik Bessembinder's study of US stock returns since 1926 points the same way: a small minority of stocks produced the net wealth creation of the whole market, and most stocks did worse than one-month Treasury bills over their lifetimes. A diversified portfolio owns that minority automatically. A concentrated one is a bet that you already hold it.

## Does owning a great company protect you?

No. It lowers the odds of failure but does not remove them. J.P. Morgan's 2024 update looked at catastrophic decliners at their peak share prices, before the fall began.

| Condition at peak price | Share of catastrophic decliners |
|---|---|
| Positive profit margins | 54% |
| Net debt-to-EBITDA of 2x or less | 63% |

More than half of the companies that later lost 70% for good were profitable on the day they peaked, and most were modestly in debt. The failures were hard to spot in advance from the financial statements.

That is the argument for managing position size rather than relying only on picking well. Analysis of moats, margins and debt tells you about durability, but it cannot rule out the competitor, rule change, product failure or fraud nobody saw coming. Position size is the only tool that works on risks you cannot see.

## Why is recovering from a big loss so hard?

A loss and the gain needed to undo it are not symmetric, because the gain starts from a smaller base.

Required gain to break even = (1 / (1 minus loss)) minus 1

| Decline | Gain needed | Years at 10% a year |
|---|---|---|
| 20% | 25% | 2.3 |
| 30% | 42.9% | 3.7 |
| 50% | 100% | 7.3 |
| 70% | 233% | 12.6 |
| 90% | 900% | 24.2 |

The last column is the one that matters. Years are computed as ln(1 / (1 minus loss)) divided by ln(1.10). A 35-year-old has decades to rebuild. A 61-year-old does not.

## Why does a concentrated position hurt more near retirement?

Because of **sequence-of-returns risk**: the order of returns, not just their average, decides whether a portfolio that funds withdrawals survives. Selling shares to pay for living costs during a decline removes those shares for good, so they cannot join the recovery.

Take a $2,000,000 portfolio paying $80,000 a year, a 4% starting withdrawal rate.

| Year 1 | Concentrated: 75% in one stock that falls 70% | Diversified: broad portfolio falls 10% |
|---|---|---|
| Single stock | $1,500,000 falls to $450,000 | Not applicable |
| Remainder (up 5%) | $500,000 rises to $525,000 | Not applicable |
| Portfolio total | $975,000 | $1,800,000 |
| $80,000 as share of portfolio | 8.2% | 4.4% |
| Gain needed to reach $2,000,000 | About 105% | About 11% |

The concentrated retiree's withdrawal rate doubled in a year without spending a dollar more. The diversified retiree faces an inconvenience. The concentrated retiree faces a different retirement.

## How do you unwind a concentrated position?

Decide the risk first, then the tax plan. These steps work in that order.

1. **Measure the position against total net worth, not one account.** Include cash, home equity and pensions. The denominator changes the answer.
2. **Set the target weight before the schedule.** Choosing 10%, 20% or zero is a risk decision. Choosing how to get there is a tax decision. If the tax bill picks the weight, it is steering your risk.
3. **Spread sales across tax years.** US long-term capital gains are taxed federally at 0%, 15% or 20%, with a 3.8% net investment income tax on top for higher earners. The IRS publishes the income thresholds each year, so check the current brackets before planning. A single huge sale stacks the whole gain into the top bracket, while several smaller sales can keep more of it in lower ones.
4. **Consider giving away the most appreciated shares.** Donating long-held appreciated stock to a qualified charity or donor-advised fund generally allows a deduction at market value without tax on the gain. This only helps if you already give.
5. **Stop adding to the position.** Reinvested dividends, vesting equity, employee stock purchase plans and option exercises all quietly rebuild what you are trying to shrink. Redirect them elsewhere.
6. **Write the schedule down.** A set number of shares each quarter removes the judgment call that concentration makes hardest. Executives use written 10b5-1 plans for legal protection, and the habit helps everyone.
7. **Ask whether the growth came from the business or the multiple.** If a holding tripled while its cash generation tripled, it trades near its starting valuation. If it tripled because investors paid a higher price for each dollar of earnings, it carries more risk than its weight alone suggests. Cluenex publishes fair value cases for about 1,000 large US-listed stocks, which is one way to check this; see [how Cluenex values stocks](https://cluenex.com/guides/how-we-value/).

## Where does this idea fail or get misused?

Concentration advice is a framework, not a rule to sell on a schedule regardless of your situation. Common mistakes:

- **"The company is excellent, so the position is safe."** Quality and size are separate risks, as the J.P. Morgan data above shows.
- **"I will diversify after it goes up a bit more."** The position is largest, and most dangerous, when it is performing best. Tying the sale to a price makes it conditional on the outcome it protects against.
- **"Capital gains tax makes selling not worth it."** A top federal rate of 23.8% (20% plus 3.8%) on the gain is a known cost. A permanent 70% decline hits the whole position, not just the profit. Tax argues for phasing, not for staying put.
- **"My concentration is employer stock in my 401(k)."** That was once the classic case. Vanguard's *How America Saves 2025* reports 8% of plans offer company stock, 93% of participants hold none and 2% hold more than 20% of their balance in it. Where it exists it is especially risky because your paycheck and savings depend on one employer. Today, a big winner in a taxable account is a more common source.
- **"An index fund means I am diversified."** Broad funds are diversified compared with one stock, not perfectly. The iShares MSCI ACWI ETF held 2,270 positions as of March 31, 2026, yet 22.95% of assets sat in its top ten holdings and 62.95% in the United States. Check the top-ten weight and largest sector.

The rule also bends when the position is a small share of wealth you do not need, or when selling would trigger a tax cost that is not worth the risk reduction. Those are judgment calls worth making deliberately.

## Example: a $2.4 million portfolio four years from retirement

An investor aged 61 holds $1,800,000 of one stock bought for $150,000, plus $600,000 in diversified funds. The stock is 75% of the $2,400,000 portfolio, with an embedded gain of $1,650,000.

Selling everything in one year would put nearly all the gain in the 20% bracket, plus the 3.8% surtax. At 23.8%, federal tax is about $392,700 (1,650,000 times 0.238), before state tax.

A phased plan could sell about $275,000 of gain a year for six years, redirect dividends and move proceeds into diversified funds. If more of each year's gain lands in the 15% bracket, the federal rate on the whole gain could fall toward 15%, about $247,500 (1,650,000 times 0.15). The gap is roughly $145,000. This is illustrative, since the real rate depends on other income, filing status and state.

The comparison that matters is a known tax cost of a few hundred thousand dollars against a 44% historical chance that a stock at some point falls 70% and never recovers, applied to a $1,800,000 position four years before withdrawals begin.

## What this means for you

If you have a regular job and a brokerage account, a few habits cover most of the risk:

- Once a year, list your holdings as a share of total net worth, and note any single stock above 10% to 15%. Pick your own limit and write it down.
- Ask what a 50% and a 70% drop in that stock would do to your plan, in dollars, and in years of work.
- Count your employer too. If your paycheck, your equity compensation and a big stock position all depend on one company, that is one risk, not three.
- Turn off dividend reinvestment into the oversized holding and route new money elsewhere.
- If you reduce, set the target weight first and a calendar second. Check current tax brackets or ask a tax professional before large sales.
- You can see a stock's business quality, main risk and insider activity on its free public page at cluenex.com/stocks/ followed by the lowercase ticker, which helps with the business-versus-multiple question.

None of this says a winner must be sold. It says the size of a position should be a choice you made, not a result you drifted into.

## Questions people ask

### What counts as a concentrated stock position?

A concentrated position is a single holding large enough that its decline would materially change your financial plan. There is no fixed percentage, since it depends on your time horizon and how much you rely on the money. A 40% weight is a bigger problem four years from retirement than thirty years away.

### How often do individual stocks suffer permanent losses?

J.P. Morgan found that 44% of companies in the Russell 3000 between 1980 and 2020 fell 70% or more from peak and never recovered. The rate ranged from 54% in Information Technology to 16% in Utilities. The same study found 66% of stocks underperformed the index over their lifetime.

### How much does a stock need to rise after a 50% loss to break even?

It needs to rise 100%, a full doubling. The formula is (1 divided by (1 minus the loss)) minus 1, so a 70% loss needs a 233% gain. At 10% a year, recovering a 70% loss takes about 12.6 years.

### What is sequence-of-returns risk?

It is the risk that the order of returns, not just the average, decides whether a portfolio that funds withdrawals lasts. Early losses hurt most because shares sold to pay expenses during a decline cannot join the recovery.

### Should I sell a concentrated position all at once?

Often not, for tax reasons rather than investment ones. A single big sale can push most of the gain into the 20% federal bracket plus the 3.8% net investment income tax, while a multi-year schedule can keep more at lower rates. Write the schedule in advance and follow the calendar, not the price.

### Are index funds immune to concentration?

No, they are less concentrated, not unconcentrated. The iShares MSCI ACWI ETF held 2,270 stocks as of March 31, 2026, yet 22.95% of assets were in its top ten holdings. Checking a fund's top-ten weight and largest sector is a quick test.

## Sources

- [The Agony & The Ecstasy: The Risks and Rewards of a Concentrated Stock Position (October 2024)](https://privatebank.jpmorgan.com/nam/en/insights/markets-and-investing/the-agony-and-the-ecstasy)
- [Do Stocks Outperform Treasury Bills?](https://www.sciencedirect.com/science/article/abs/pii/S0304405X18301351)
- [How America Saves 2025](https://institutional.vanguard.com/insights-and-research/report/how-america-saves.html)
- [Topic no. 409, Capital gains and losses](https://www.irs.gov/taxtopics/tc409)
- [Topic no. 559, Net investment income tax](https://www.irs.gov/taxtopics/tc559)
- [iShares MSCI ACWI ETF (ACWI)](https://www.ishares.com/us/products/239600/ishares-msci-acwi-etf)

Cite as: Cluenex. "Concentrated Stock Positions: The Risk Hiding in Your Best Winner." Cluenex Learn, updated Oct 15, 2026. https://cluenex.com/learn/portfolio-management/concentrated-stock-position/