How to Use Position Sizing Across Your Investment Strategy
By Oliver Grant profile image Oliver Grant
5 min read

How to Use Position Sizing Across Your Investment Strategy

Position sizing is an important yet often overlooked strategy that determines how much to invest in a particular stock or asset.

It's essentially about finding the right balance by investing enough to make meaningful gains while not risking so much that a single misstep could jeopardize your financial health.

Think of position sizing like adding ingredients to a recipe. Too much of one ingredient can throw off the balance, while too little can make the dish taste bland. By carefully measuring each ingredient, you create a delicious meal. 

Similarly, by allocating the right amount of money to each investment, you build a strong, balanced portfolio that can handle market changes and grow steadily over time. That said, position sizing is based not only on your total capital but also on an assessment of the risk associated with each potential investment.

Why Is Position Sizing Important?

The ultimate goal of position sizing is to maximize returns while minimizing risk, ensuring that no single trade can significantly harm the overall portfolio. That said, let’s look at it in a bit more detail:

  • Risk management. Every investor has a different level of comfort with risk. Position sizing tailors your investments by limiting the amount you invest based on potential loss, you can use stop-loss orders to automate the existing process at a predetermined price to limit potential losses.
  • Maximizing returns. By allocating capital to different investments, position sizing helps you take full advantage of profitable opportunities. Just focus on diversifying your investments across different stocks and asset classes (like bonds, commodities, and real estate) to spread risk.
  • Drawdown reduction. Position sizing helps minimize drawdowns during market downturns by limiting the impact of individual losses on the overall portfolio. This is crucial for preserving capital and maintaining long-term growth, as deep drawdowns can significantly impair your portfolio's ability to recover and achieve its objectives.

4 Methods of Position Sizing

Selecting the right method for position sizing can significantly impact the effectiveness of your investment strategy. Here’s a look at some common approaches:

1. Fixed Unit Size

This means you allocate a fixed quantity of shares or units to each trade, regardless of the underlying price or volatility. For example, if your fixed unit size is 100 shares, you'll buy 100 shares of Stock A at $50 and 100 shares of Stock B at $100. 

Basically, you’re buying a set number of stocks without considering the price difference. So, it’s best for investors who appreciate simplicity and have a relatively uniform risk profile across investments.

Investment Formula: Number of Shares = Fixed Unit Size

2. Percentage Risk Model

In this model, you need to invest a fixed percentage of your portfolio in each position, adjusting the dollar amount invested based on the overall portfolio size and the specific risk of the investment.

For example, if your portfolio is worth $100,000 and you want to risk 2% per trade, you'll invest $2,000 in each position. This means if Stock A is trading at $50, you'll buy 40 shares ($2,000 / $50). It’s best for investors looking to balance risk proportionately across various investments.

Investment Formula: Number of Shares = (Portfolio Value × Risk Percentage) / Stock Price

3. Dollar Amount Risk Model

Choose to risk a fixed dollar amount on each investment, providing straightforward calculations and consistent risk management. Let’s say you're willing to risk $1,000 per trade, and Stock A is trading at $50 with a stop-loss at $45, you'll buy 200 shares. 

If the stock hits the stop-loss, your loss will be limited to $1,000 (200 shares × $5 loss per share). So, it’s best for investors to have a clear understanding of their maximum risk capacity per trade.

Investment Formula: Number of Shares = Dollar Amount at Risk / (Entry Price - Stop Loss Price)

4. Kelly Criterion

This method uses a mathematical formula to determine the optimal size of a bet based on past performance probabilities and expected outcomes. For example, if a stock has a 60% chance of generating a 10% return and a 40% chance of a 5% loss, the Kelly Criterion would suggest investing 20% of your portfolio in that stock.

It's best for more advanced investors who are comfortable with mathematical optimization in their investment decisions.

Investment Formula: Position Size = (Win Probability × Win Amount - Loss Probability × Loss Amount) / Win Amount

How to Implement Position Sizing in Your Investment Strategy

Implementing position sizing requires a strict approach and a clear understanding of your investment landscape. Here are a few practical steps to help you incorporate position sizing into your strategy:

1. Calculate Your Risk Tolerance

The easiest way to calculate your risk tolerance is by dividing your potential net profit by your maximum potential loss. When that’s done, you can follow these three options:

  • Low risk tolerance. Invest in a well-established company with steady growth of about 5-6% annually.
  • Moderate risk tolerance. Invest in a mix of well-established companies and startups with steady growth and moderate risk andreturns of about 10-14% yearly.
  • High risk tolerance. Invest in startups or newer companies with potential for high returns of 15-20% annually but with higher risk due to increased likelihood of failure.

2. Choose a Position Sizing Method

Select the position sizing model that best fits your risk tolerance and investment style. For example:

  • Low-risk tolerance (less than 60%). Use the “fixed unit size” or “dollar amount risk” models to maintain a conservative approach.
  • Moderate risk tolerance (60-80%). Consider the “percentage risk model” to balance risk proportionately across investments.
  • High-risk tolerance (above 80%). Explore the “Kelly criterion” or a combination of methods to optimize returns while managing risk.

3. Determine Stop-loss Levels

Set clear stop-loss points to automatically sell off assets that perform poorly, limiting your losses. For example, if you buy a stock at $100, you might set a stop-loss at $90, which means the stock will automatically be sold if it drops to $90, limiting your loss to 10%.

It’s also better to spread investments across various sectors and asset classes to mitigate risk. For example, you can allocate 60% to stocks (e.g., 20% to technology, 20% to healthcare, 20% to consumer goods), 30% to bonds, and 10% to real estate to diversify your portfolio and mitigate risk.

4. Regularly Review and Make Adjustments

You can also adjust your position sizes based on your short-term and long-term financial goals. Larger positions are for aggressive growth, while smaller, safer positions are suited for long-term, steady growth. For example: 

  • If you're saving for a down payment on a house in 5 years, you can allocate 70% to stable, income-generating investments like bonds and 30% to growth-oriented stocks. 
  • If you're saving for retirement in 30 years, you might allocate 80% to stocks and 20% to bonds to prioritize long-term growth.

5. Be Consistent and Track Market Conditions

Consistent use of position sizing rules across your portfolio helps in achieving steady growth. It also reduces the impact of emotional decision-making, leading to a more standard investing process. 

Just make sure to regularly update your investment strategy based on current economic indicators and market trends to ensure it remains effective.

Wrapping Up

Effective position sizing is crucial for managing investment risks and achieving financial goals. By understanding and implementing various position sizing methods, regularly reviewing your portfolio, and avoiding common pitfalls, you can enhance your ability to navigate the complexities of the market. 

Remember, the goal is not just to invest but to invest wisely — position sizing is a fundamental tool in achieving this. Stay disciplined, stay informed, and let your investment strategy evolve as you grow as an investor.

Please note that while our research is grounded in analyses conducted by market professionals, it should not be construed as direct investment advice. We are not registered investment advisors. As such, we offer insights intended to provide you with well-informed perspectives, aiming to assist you in making educated decisions. However, we do not provide warranties regarding the accuracy or completeness of the information presented. Any investment decisions you make are at your sole discretion and responsibility.
By Oliver Grant profile image Oliver Grant
Updated on
Learning Hub