Find Great Stocks and Build an Efficient Portfolio with My Stock Screener and Portfolio Builder
- Sanzhi Kobzhan
- Oct 30, 2025
- 9 min read
Updated: Dec 18, 2025
Investing successfully means finding the right stocks for your risk appetite and combining them into a strong, diversified portfolio. My Stock Screener and Portfolio Builder app is designed to do exactly that. It allows you to find great stocks tailored to your risk profile and then construct an efficient investment portfolio using the Nobel Prize-winning Markowitz model.
In this guide, I explain how the app works and provide a step-by-step tutorial to help both beginners and experienced traders make the most of its features. The tool is available as a web application and as an iOS app called Stocks 2 Buy, so you can choose the platform you prefer.
Tailor Your Investment Search to Your Risk Appetite
Every investor is different when it comes to risk. Risk appetite refers to how much uncertainty or volatility you are willing to tolerate in pursuit of returns. My stock screener lets you specify your risk level upfront so that it can filter stocks accordingly:
Low Risk: If you select a low risk appetite, the screener will emphasize stable, established companies. These tend to have low beta (meaning their stock price is less volatile than the market) and large market capitalizations, indicating mature businesses. They also typically have high trading volumes (high liquidity), ensuring you can buy or sell easily. In practical terms, choosing low risk filters for stocks that generally experience smaller price swings and are of substantial size, which can offer more predictable performance.
High Risk: If you choose a high risk appetite, the screener opens the door to more volatile opportunities. It will include stocks with higher beta values (stocks that fluctuate more dramatically than the overall market). It still focuses on mid to large companies with solid trading volume, but the selected stocks may have higher growth potential and volatility. This setting is for investors willing to accept bigger short-term swings in exchange for the possibility of higher returns.
By letting the app know your risk tolerance, you ensure that the list of stocks you get is tailored to your comfort level– whether you’re a conservative investor seeking stability or an aggressive investor seeking growth. Even if you’re new to these terms, the app handles the filtering automatically; you just decide which risk category fits you best.
Define Your Target Return
Another key input in my Stock Screener and Portfolio Builder is your desired return. Using a simple slider interface, you can set your target annual return (from 1% up to 50%). This target is used later by the portfolio builder portion of the app. Essentially, you are telling the app the kind of returns you hope to achieve with your investment portfolio.
If you set a modest target return, the resulting portfolio will be more conservative (lower risk) because it doesn’t need to stretch for very high returns.
If you set a high target return, be aware that this usually comes with higher risk. The app will still find a portfolio that attempts to meet that return, but expect that the portfolio’s volatility may be higher in order to reach a more ambitious goal. (The risk–return tradeoff is fundamental in investing – higher expected returns typically require taking on higher risk.)
Note: The target return is used for portfolio construction. It doesn’t guarantee that exact return – rather, it guides the optimization model to aim for that return based on historical data. The app uses roughly one year of historical prices to estimate returns and volatility for each stock. Keep in mind that all projections are based on past data, and past performance is not a guarantee of future results. However, setting a clear goal helps the model shape an investment mix that aligns with your expectations.
Screening for Stocks: Filters and Results
With your risk appetite (low or high) selected and your desired return set, you can further refine your search using optional filters for stock exchange and country:
Exchange Filter: You can limit the search to a specific stock exchange if desired (e.g. NASDAQ, NYSE, AMEX). Leaving it blank will include stocks from all major exchanges.
Country Filter: Similarly, you can filter stocks by country (e.g. US, CA for Canada, GB for United Kingdom, JP for Japan, etc.). By default, it’s not restricted by country unless you choose one.
These filters allow you to focus on certain markets or regions if that’s important to your strategy. For example, an investor who only wants U.S. stocks can select US under country, and the screener will only show U.S.-based companies.
Once you’ve set the inputs (chosen risk level, set return, and any filters), it’s time to screen for stocks:
Stock Screener and Portfolio Builder
Run the Screener
Click the “Screen Stocks” button. The app will connect to the live financial data and retrieve up to 100 stocks that match your criteria. A loading indicator will show the progress, and within moments, you’ll see a table of results appear under the Results section.
Understanding the Results
The results table will list each matching stock along with key data:
Symbol: The ticker symbol of the stock. This acts as a quick identifier (e.g., AAPL for Apple Inc.).
Company: The full name of the company.
Price: The latest stock price.
Beta: The stock’s beta value, which indicates volatility. A beta around 1 means the stock moves with the market. Below 1 means less volatile than the market, above 1 means more volatile. This column is useful to quickly see how risky a stock might be relative to others.
Market Cap: The company’s market capitalization (the total value of its shares). This is formatted for convenience (e.g., 250B for $250 billion). Larger market caps often imply more established companies.
Volume: The average trading volume, which reflects liquidity. A higher number means the stock is traded heavily (easier to enter/exit positions without big price changes).
Exchange: Which exchange the stock is listed on (e.g., NASDAQ, NYSE).
Country: The country of the company’s primary listing.
By default, the list is ordered with the most liquid, high-volume stocks at the top. This means you’re likely seeing the larger, more actively traded companies first. If no stocks appear or the list is empty, the app will show a message (for instance, if your criteria are too restrictive or if there was an issue fetching data). You can always adjust the filters and try again.
Reviewing and Picking Stocks
Go through the list and take note of the companies and metrics. Thanks to the initial risk filter, all these stocks already fit your risk preference. For example, in a low-risk search you might see utility companies or large tech firms with stable performance, whereas a high-risk search might show more cyclical or growth-oriented companies. If you want more information on a particular stock, the app lets you dig deeper – simply click on a stock’s symbol to open a detailed analysis. A pop-up window will display rich data about that company’s financials, charts, and other analysis. This helps you do quick due diligence without leaving the app.
At this stage, you have a curated list of candidates that suit your risk appetite. The next step is optional but highly valuable: you can use the Portfolio Builder to combine some of these stocks into a theoretically optimal portfolio.
Building an Efficient Investment Portfolio (Markowitz Model)
One of the standout features of my app is the built-in portfolio builder, which uses Harry Markowitz’s modern portfolio theory to create an efficient portfolio from the stocks you select. In simple terms, an efficient portfolio is one that maximizes return for a given level of risk or minimizes risk for a given target return. The idea is to take advantage of diversification – by mixing stocks that don’t move in lockstep, you can reduce overall volatility while meeting your return goals.
Here’s how to use the portfolio builder step by step:
Select Your Stocks
From the screening results, choose a set of stocks that you want to include in your portfolio. You can do this by checking the box next to each stock in the list. The app will show a count of how many you’ve selected (e.g., “5 selected” will appear next to the Results header).
Expert Tip: You should select at least 5 stocks to build a well-diversified portfolio (the “Build Portfolio” button will become available once you have picked five or more). You can also use the master checkbox at the top of the table to quickly select or deselect all stocks, then fine-tune your choices.
Build the Portfolio
Click the “Build Markowitz Portfolio” button (it appears once enough stocks are selected). The app will now perform the heavy lifting. It retrieves historical price data for each chosen stock (approximately one year of daily data) and calculates the mean return and volatility of each, as well as how each stock’s returns correlate with the others.
Using the Markowitz optimization model, it then finds the optimal weight for each stock in the portfolio that achieves your desired return with the lowest possible risk. In other words, it solves for the portfolio that hits the target return you set earlier, while minimizing the portfolio’s overall standard deviation (risk). This is the essence of Modern Portfolio Theory: by mathematically balancing the weights, the tool identifies how much to allocate to each stock to be on the efficient frontier for the return you want.
View Portfolio Results
Once the calculation is done (usually within a few seconds), a new section called Efficient Portfolio (Markowitz) will appear. Here you’ll see:
A summary line stating the Target return you requested and the Minimized risk achieved. Risk is expressed as an annualized standard deviation (σ). For example, it might say “Target return: 12% · Minimized risk (σ, annual): 8%”, meaning the portfolio was constructed to aim for a 12% annual return with an 8% volatility.
A table of your selected symbols and their recommended weights in the portfolio. Each stock you selected is listed with a percentage weight. Positive percentages indicate a long position (buying that portion of the portfolio in that stock). In some cases, you might see a small negative percentage for a stock – this implies a short position, meaning the model suggests short-selling a bit of that stock to hedge risk. (Short positions can appear when the model finds that doing so reduces overall volatility; this is part of allowing “short weights” to minimize risk. If you prefer not to short any stock, you could manually adjust or ignore those slight negatives, but the presence of a negative weight is a result of pure mathematical optimization.)
A visual bar indicator for each allocation to help you quickly see the relative sizes of the positions.
The allocation table essentially tells you how to distribute your investment across the chosen stocks to form an efficient portfolio. For example, it might suggest putting 30% of your capital in Stock A, 25% in Stock B, 20% in Stock C, and so on (with some weights possibly negative or over 0% if shorting or leveraging is involved).
Interpretation and Next Steps
What does this optimized portfolio mean for you? It provides a model allocation that, based on recent historical data, would have achieved your target return with minimal volatility. This gives you a starting point for a diversified portfolio aligned with your goals.
If the target return you set was too high to realistically achieve (for instance, asking for 50% annual return with only low-risk stocks), you might notice the “Minimized risk” is still quite high or the weights look unusual. In extreme cases, the model will do what it can – for instance, it might allocate more to the highest-return stocks or use short positions – but real-world constraints might make such a portfolio impractical. It’s important to set a reasonable target return and to use the output as guidance. You can always go back and adjust your selections or target and rebuild to see different scenarios.
Finally, remember that the Markowitz model is based on historical correlations and returns. While it’s a powerful tool for understanding the risk/return tradeoff and diversification benefits, no model can predict the future perfectly. Use the portfolio suggestion as a well-informed guide, and combine it with your own research and judgement. The good news is that the app’s integrated stock analysis feature (accessible by clicking any stock symbol in the results) can assist you in researching each asset further before you commit to an investment strategy.
Smarter Investing with an Integrated Screener and Portfolio Tool
Investing can seem complex, but the right tools make it more approachable. My Stock Screener and Portfolio Builder simplifies the process by combining easy-to-use stock discovery with sophisticated portfolio optimization. Whether you’re a beginner trying to find your first set of stocks or an experienced analyst looking to save time, this app provides a clear, data-driven path to building a portfolio tailored to your personal risk and return objectives.
It embodies a professional, credible approach – using well-established financial principles like risk-return tradeoff and diversification – and delivers the results in a user-friendly interface.
With this app, you don’t need advanced financial training to apply advanced concepts. You can confidently identify stocks that fit your risk profile and let the Markowitz model show you an efficient way to allocate your investments.
The outcome is a portfolio suggestion designed to maximize your returns for the level of risk you’re willing to take. In practice, this means you’re not just picking stocks at random or chasing trends; you’re constructing a balanced strategy backed by quantitative analysis.