Portfolio Concentration

Introduction

In lessons I-038–I-041, we progressively built the management of risk at the individual trade level.

We learned to:

determine the maximum risk we are willing to take per trade,

calculate risk per unit from the stop distance,

determine position size from that risk,

use Fixed Fractional Sizing to adapt risk to current account size,

and use Volatility-Based Sizing to account for differences in how much individual instruments typically move.

A new question now arises:

What happens when the risk of every individual trade is appropriate, but we take too much risk at the portfolio level at the same time?

Suppose we trade three different stocks and each has a maximum trade risk of 1%. At first glance, everything may appear correct.

But if all three stocks belong to the same sector, move similarly, or are driven by the same market event, the three positions do not necessarily represent three independent risks.

At portfolio level, a single common market event could cause a significant loss.

Therefore, professional risk management cannot stop at the question:

“How much are we risking in this trade?”

We must also ask:

“How much are we risking in total, and which risks are concentrated in our portfolio?”

1. What Is Portfolio Concentration?

Portfolio Concentration means that a significant portion of a portfolio’s value, risk, or exposure is connected to one common factor.

This can be:

a single instrument,

a single sector,

a single industry,

a single market direction,

a single economic factor,

a single currency,

or several positions that move strongly together.

Concentration is not automatically a mistake.

The problem arises when we do not know the degree of concentration or do not manage its associated risk deliberately.

For example:

we hold five different stocks,

but all five are technology companies,

and all five react strongly to the same Nasdaq movement.

On paper, we have five different positions.

From a risk perspective, however, we may effectively be taking the same market exposure five times.

2. The Number of Positions Is Not the Same as Diversification

This is one of the most important distinctions.

Having 10 positions in a portfolio does not automatically mean that the portfolio is well diversified.

For example:

10 technology stocks,

10 different stocks from the same industry,

10 instruments exposed to the same macroeconomic event.

The position count is high, but the portfolio can remain highly concentrated because of common risk factors.

By contrast, a smaller number of positions with less dependence on one another can, in some circumstances, provide a more balanced risk structure.

Therefore, we should not ask only:

“How many trades are open?”

We should also ask:

“What risks stand behind these trades?”

3. Risk per Trade and Portfolio Risk

In I-038 we worked with risk per trade.

For example:

account: $20,000,

Risk %: 1%,

maximum trade risk: $200.

If we open three different positions and risk 1% in each, then by simple addition:

Trade A: 1%

Trade B: 1%

Trade C: 1%

Total:

3% initial planned risk.

But this is only the first layer.

If the three positions are strongly correlated, their overall market sensitivity may be greater than what we perceive by simply counting the trades.

Therefore, portfolio risk should not be interpreted solely as the sum of individual stops.

4. What Is Correlation Risk?

Correlation Risk arises when multiple positions may react similarly to the same market movement.

For example, we have three stocks:

A: a chip manufacturer,

B: a semiconductor company,

C: a technology infrastructure company.

They may be separate companies.

However, if a strong technology-sector selloff begins, all three may fall together.

This means that the positions do not behave as independent risks.

Correlation can also change over time.

Two instruments may move together only moderately in normal conditions, while their relationship may become much stronger during severe market stress.

This matters because diversification benefits can decrease during periods of market stress.

5. Nominal Exposure and Risk Are Different

As we saw in I-039, we must distinguish position value from risk.

The same applies at portfolio level.

Suppose:

account: $20,000,

three positions,

each with a nominal value of $5,000.

Total nominal exposure:

$15,000.

That does not mean our risk is $15,000.

If each position has $200 of initial stop risk, total planned initial risk is:

$600 = 3% of the account.

These are completely different numbers:

$15,000 nominal exposure

$600 planned initial risk

Professional risk management requires us to monitor both.

6. Why Can Apparently Different Positions Be Dangerous?

Imagine a portfolio with five positions:

A: +1R risk,

B: +1R,

C: +1R,

D: +1R,

E: +1R.

Total initial risk:

5R.

If the positions have completely different risk factors, this may be acceptable under a particular portfolio model.

If all five are sensitive to the same market factor, however, one significant market event could trigger several stops.

The losses are then not independent.

Because of the common risk factor, several positions can be damaged simultaneously.

7. Main Forms of Portfolio Concentration

Concentration can arise in several ways.

Instrument concentration

Too much weight is placed in a single instrument.

Sector concentration

Several different stocks belong to the same sector.

Industry concentration

Positions are concentrated in companies from the same industry.

Market concentration

Several positions depend on the movement of the same market.

Currency concentration

The outcome of several positions is connected to the same currency.

Factor concentration

Positions are sensitive to the same factor, such as:

interest-rate conditions,

economic growth,

inflation,

market volatility.

Concentration therefore does not mean only “too much money in one stock.”

It is a much broader risk concept.

8. Correlation Is Not Constant

We should not assume that two instruments will always have the same level of correlation.

Market conditions change, and relationships change with them.

For example:

In a calm market:

A and B may move only moderately together.

In a strong market decline:

A and B may begin falling together.

Therefore, historical correlation is information, not a guarantee.

We can use past relationships to understand risk, but we should not assume that every future market environment will behave in the same way.

9. Concentration and Drawdown

Portfolio concentration can directly influence Drawdown.

Suppose many similar positions are held at the same time.

If that market segment enters an unfavorable period:

several stops may be triggered,

the account may decline faster,

drawdown may become larger,

and recovery may take longer.

The problem is therefore not simply that “we lost several trades.”

The problem is that the same risk factor caused several losses at once.

10. Fixed Fractional Sizing Does Not Solve Everything

In I-040 we saw that Fixed Fractional Sizing adapts individual trade risk to current account size.

That is important.

But it does not by itself guarantee appropriate portfolio risk.

If, for example:

we open 10 trades,

each has 1% risk,

and a significant portion of them are correlated,

then the individual positions may be correctly sized while the overall portfolio remains excessively concentrated.

Professional risk management therefore has two levels:

Trade level → Portfolio level

The first asks:

“How much are we risking in this individual trade?”

The second asks:

“How much are we risking in total, and what common risk factors are present?”

11. The Role of Volatility at Portfolio Level

In I-041 we saw that volatility can influence individual position sizing.

It is also important at portfolio level.

If we hold several high-volatility positions simultaneously, the portfolio may move much more intensely.

For example:

A: high volatility,

B: high volatility,

C: high volatility.

If they are also strongly correlated, the combination can create substantially greater portfolio risk.

Therefore, it is not enough to say:

“Each trade is 1%.”

We should also examine:

how volatile they are,

how correlated they are,

how large the nominal exposure is,

and which common market factor drives them.

12. A Simple Portfolio Risk Framework

At intermediate level, we can use a simple control framework.

For every open position, ask:

1. What is the individual risk?

2. What is the nominal position value?

3. What is its weight relative to the portfolio?

4. Which other positions may move with it?

5. Is there a common sector or market exposure?

6. What is the total initial risk?

7. What would happen if several positions became losers at the same time?

This is already a much more advanced approach than examining individual stops alone.

13. A Simple Portfolio Example

Let:

account: $30,000,

trade risk: 1%,

maximum risk per trade: $300.

We have three positions:

A: technology stock,

B: technology stock,

C: technology stock.

Each has $300 of planned initial risk.

Total:

$900 = 3%

On paper, every trade complies with the 1% rule.

But all three positions belong to the same sector.

If a strong technology-sector selloff develops, all three positions may come under pressure at the same time.

Therefore, we should not simply say:

“We have three separate trades.”

A better description is:

“We have three trades containing a significant common risk factor.”

14. Successful Case Study

We have a $50,000 account.

Maximum trade risk:

1% = $500

We identify three setups:

A: technology stock,

B: healthcare stock,

C: energy stock.

Each has $500 of planned initial risk.

Total:

$1,500 = 3%

The positions belong to different sectors and are influenced by different market factors.

They are not guaranteed to be independent, but concentration may be lower than with three similar technology positions.

Risk management here does not mean that we automatically make every position smaller.

It means that we take the structure of the entire portfolio into account.

15. Failed Case Study

The same $50,000 account.

Three trades:

A: $500 risk,

B: $500 risk,

C: $500 risk.

All three are connected to the same narrow technology market segment.

The trader thinks:

“Each trade is only 1%, so it is safe.”

That can be misleading.

After a negative sector-wide event:

A reaches its stop,

B reaches its stop,

C reaches its stop.

Loss:

-$1,500 = -3%

If more similar positions were open, the effect could be even greater.

The problem was not necessarily individual position sizing.

The problem was ignoring portfolio-level concentration.

16. Why Is the “Many Small Trades” Approach Dangerous?

It is easy to believe that a portfolio is safe because it contains many small positions.

That is only partly true.

Ten small positions can still represent one large risk bet if they are all sensitive to the same market event.

For example, ten stocks may be:

in the same sector,

components of the same index,

exposed to similar fundamental factors,

or built around similar technical structures.

The position count is high, but risk diversification is low.

Therefore, we should examine the number and concentration of risk factors, not only the number of positions.

17. When Should We Consider Reducing Combined Position Risk?

Reducing portfolio risk can be especially appropriate when:

several positions are strongly correlated,

one sector has too much weight,

one market event could affect several trades,

total nominal exposure is high,

volatility is high,

leverage is being used,

we are in significant drawdown,

or several strategies point in the same direction.

Possible responses include:

smaller position sizes,

fewer simultaneous trades,

lower individual Risk %,

risk limits between correlated positions,

or skipping certain positions.

The specific rule should always be defined by our own trading system.

18. Portfolio Risk and 1R

R-multiple allows us to interpret different trades using a common risk unit.

If:

1R = $300

then:

A = 1R,

B = 1R,

C = 1R.

Together:

3R of initial risk.

This simplifies interpretation of portfolio risk.

However, the sum of R values still does not tell us about correlation.

3R across three independent positions can represent a different risk structure from 3R across three highly correlated positions.

19. Leverage and Portfolio Concentration

Leverage can increase the importance of concentration.

If margin allows us to take larger nominal positions, total market exposure can become significantly larger than the account's own capital.

That does not automatically make a trade wrong.

However:

larger exposure + high volatility + correlated positions = potentially much greater portfolio risk.

Therefore, when using margin, relationships between positions deserve particular attention.

20. What Happens When We Use Multiple Strategies at Once?

Concentration can occur even across different positions and strategies.

For example:

a breakout strategy opens a long position,

a momentum strategy also opens a long position,

a trend-following strategy is also long.

Technically, three different strategies are operating.

At portfolio level, however, all three may point in the same direction.

If the market suddenly reverses, all three strategies may lose at the same time.

Therefore, strategy diversification does not automatically mean risk diversification.

21. Concentration Is Not Always Bad

It is important not to move to the opposite extreme.

Concentration itself is not prohibited.

A trading system may deliberately take concentrated exposure.

The question is not:

“Can we have a concentrated portfolio?”

The question is:

“Do we know how concentrated it is, and are we willing to accept its consequences?”

A deliberately concentrated system can be fully controlled.

The main problem is usually unrecognized concentration.

22. How Do We Audit Portfolio Concentration?

During a simple portfolio audit, we can build a table containing:

position,

risk,

nominal value,

sector,

direction,

possible common factor.

For example:

A: 1R, $5,000, technology, long, Nasdaq

B: 1R, $4,000, technology, long, Nasdaq

C: 1R, $3,000, energy, long, oil

D: 1R, $6,000, healthcare, long, defensive

We can now see not only that four trades are open.

We can also see that A and B contain a common risk factor.

The next question is:

“Is this level of concentration acceptable to us?”

23. The Professional Approach

A professional portfolio risk system can define in advance:

maximum Risk % per trade,

maximum total initial risk,

maximum sector exposure,

maximum correlated exposure,

maximum nominal exposure,

maximum leverage,

maximum risk allowed at different drawdown levels,

restrictions during high-volatility conditions.

These rules do not have to be identical for everyone.

The important point is that they are defined in advance rather than invented during a losing situation.

24. Portfolio Concentration and Psychology

Concentration can also create a psychological problem.

If several similar positions are held at once, the entire portfolio can move faster.

During a sudden market decline we may experience:

several losing positions simultaneously,

several stops being approached,

rapidly falling equity,

increased stress.

This can make it easier to:

move stops,

hold losing positions too long,

increase risk,

or open impulsive new trades.

A good portfolio risk system therefore has to be not only mathematically correct, but also psychologically executable.

25. Common Mistakes

1. Looking only at individual trade risk

Every trade is 1%, so we assume the portfolio is safe.

2. Treating position count as diversification

Many positions do not necessarily mean many independent risk factors.

3. Ignoring correlation

We treat separate stocks as separate risks.

4. Looking only at nominal value

Large position value and large risk are not the same thing.

5. Ignoring volatility

Several high-volatility, correlated positions can create substantial portfolio movement.

6. Treating historical correlation as a guaranteed future relationship

Market relationships can change.

7. Looking only at margin requirements when using leverage

Margin is not the same as total risk.

8. Having no portfolio-level limit

Every individual trade is within its rule, but total risk is excessive.

26. The Essence of Portfolio Concentration

Portfolio risk cannot be understood solely by adding up individual trades.

Professional thinking examines risk at three levels:

1. Individual trade

How much risk do we take in this trade?

2. Portfolio

How much total open risk do we have?

3. Common risk factors

How strongly do these positions depend on the same market factors?

The goal is not necessarily to make every position completely independent.

The goal is to know our portfolio concentration and regulate risk accordingly.

In I-038–I-041 we learned how to control individual trade risk.

In I-042 we take that thinking one level higher:

we begin to manage not only individual trades, but the structure of the entire risk system.

Practical Exercise

Create a simple portfolio audit using at least 10 current or hypothetical positions.

For each position, record:

instrument,

position size,

entry price,

stop,

initial risk,

1R,

nominal position value,

sector,

market direction,

related index or market factor,

estimated correlation relationship.

Then:

1. Individual risk

Calculate the Risk % of every position.

2. Total risk

Add together the initial risk of all open trades.

3. Sector concentration

Identify which sector contains the largest risk exposure.

4. Correlation

Find at least three positions that are expected to move similarly in a given market environment.

5. Stress test

Assume that all correlated positions reach their stops at the same time.

Calculate the portfolio loss in USD and as a percentage of the account.

6. Portfolio-level rule

Define at least one rule that limits excessive concentration.

The goal is not to find one universally correct limit, but to become able to recognize hidden concentration in our portfolio.

Key Terms

Portfolio Concentration — Portfólió-koncentráció

Risk Management — Kockázatkezelés

Position Sizing — Pozícióméretezés

Risk per Trade — Ügyletenkénti kockázat

Correlation Risk — Korrelációs kockázat

Exposure — Kitettség

Portfolio Risk — Portfólió-kockázat

Nominal Position Value — Nominális pozícióérték

Drawdown — Visszaesés / Drawdown

Fixed Fractional Sizing — Fix frakcionális

Volatility-Based Sizing — Volatilitásalapú méretezés

Volatility — Volatilitás

ATR

Stop Loss

Stop Distance — Stop távolság

R-multiple

1R

Leverage — Tőkeáttétel

Margin

Knowledge Check

1. What is portfolio concentration, and why can it create risk?

2. Why does a high number of positions not automatically mean that our portfolio is diversified?

3. What is the difference between risk per trade and portfolio risk?

4. What is correlation risk?

5. Why can holding several strongly correlated positions at the same time be dangerous?

6. Why is nominal position value not the same as actual trade risk?

7. How can portfolio concentration increase drawdown?

8. Why does Fixed Fractional Sizing alone not solve the portfolio concentration problem?

9. How are volatility and correlation connected to portfolio risk?

10. Why can three different strategies still represent exposure to the same common market risk?

11. Why is a portfolio-level risk limit important in addition to an individual trade limit?

12. Why can historical correlation not be treated as a guaranteed future relationship?

13. Why can excessive portfolio concentration also be psychologically dangerous?

14. What is the difference between instrument, sector, market, and factor concentration?

15. What is the most important objective of professional portfolio risk management regarding concentration?

Az Akadémia szöveges tartalmának részben, vagy egészben történő másolása, többszörözése, átdolgozása, terjesztése, valamint nyilvános bemutatása a szerző előzetes, írásos hozzájárulása nélkül tilos.