# Use Monte Carlo analysis to estimate risk

The Monte Carlo model allows researchers from all different occupations to conduct multiple experiments to define all potential outcomes of an event or decision. In the financial industry, decision-making is usually related to investment. After merging, all individual trials will create a probability distribution or risk assessment for a given investment or event.

Monte Carlo analysis is a multivariate modeling technique. All multivariate models can be considered as complex statements of “what if…?” Scenes. Some of the most well-known multivariate models are models used to evaluate stock options. Research analysts use them to predict investment results, understand the likelihood of investment risks surrounding them, and better reduce risk.

When investors use the Monte Carlo method, compare the results with various risk tolerances. This can help stakeholders decide whether to continue investing.

### Key points

• The Monte Carlo model allows researchers from all different occupations to conduct multiple experiments to define all potential outcomes of an event or decision.
• When using the Monte Carlo model, the user changes the values ​​of multiple variables to determine their potential impact on the decision being evaluated.
• In the financial industry, decision-making is usually related to investment.
• The probability distribution generated by the Monte Carlo model creates a risk map.

## Who uses the multivariate model

Multivariate models (such as Monte Carlo models) are popular statistical tools that use multiple variables to predict possible outcomes. When using a multivariate model, users change the values ​​of multiple variables to determine their potential impact on the decision being evaluated.

Many different types of occupations use multiple models. Financial analysts may use multivariate models to estimate cash flow and new product ideas. Portfolio managers and financial advisors use them to determine the impact of investments on portfolio performance and risk. Insurance companies use them to estimate the likelihood of claims and to price insurance policies.

The Monte Carlo model is named after geographic location, and Monte Carlo (strictly speaking, an administrative area of ​​the Principality of Monaco) is famous for its proliferation of casinos.

### Outcome and probability

For games of chance—just like games played in casinos—all possible outcomes and probabilities are known. However, for most investments, the set of future results is unknown.

It is up to the analyst to determine the outcome and its probability of occurrence. In Monte Carlo modeling, the analyst runs multiple experiments (sometimes even thousands) to determine all possible outcomes and their probability of occurrence.

Monte Carlo analysis is useful because many investment and business decisions are made based on one result. In other words, many analysts deduce a possible situation and then compare the result with various obstacles to that result to decide whether to proceed.

### Formal estimation

Most preparation estimates start from the basic situation. By entering the highest probability hypothesis for each factor, the analyst can arrive at the highest probability result. However, making any decision based on the basic situation is problematic. It is not enough to create a prediction of the outcome, because it does not account for any other possible values ​​that may occur.

It has not yet stated that the actual future value will be the true probability of something other than the basic situation forecast. If the driving factors and probabilities of these events are not calculated in advance, it is impossible to hedge negative events.

## Create a model

After the design is completed, a tool is needed to execute the Monte Carlo model, which will randomly select factor values ​​constrained by certain predetermined conditions. By running a large number of experiments using variables that are constrained by their own independent probability of occurrence, the analyst creates a distribution that includes all possible outcomes and the probabilities that they will occur.

There are many random number generators on the market. The two most common tools for designing and executing Monte Carlo models are @Risk and Crystal Ball. Both can be used as plug-ins for spreadsheets and allow random sampling to be incorporated into established spreadsheet models.

### Right constraint

The trick to developing a suitable Monte Carlo model is to determine the correct constraints for each variable and the correct relationship between the variables. For example, since portfolio diversification is based on the correlation between assets, any model developed to create the expected portfolio value must include the correlation between investments.

In order to choose the correct distribution for a variable, it is necessary to understand every possible distribution available.For example, the most common is the normal distribution, also known as the bell curve.

### Normal distribution and standard deviation

In the normal distribution, all occurrences are evenly distributed around the mean. The average is the most likely event. Natural phenomena, human height and inflation are some examples of input normal distributions.

In Monte Carlo analysis, the random number generator selects a random value for each variable within the constraints set by the model. Then it generates a probability distribution for all possible outcomes.

The standard deviation of the probability is a statistic that represents the probability that the actual result being estimated is not the average or the most probable event. Assuming that the probability distribution is normally distributed, approximately 68% of the values ​​will fall within one standard deviation of the mean, approximately 95% of the values ​​will fall within two standard deviations, and approximately 99.7% will fall within three of the average Within the standard deviation.

This is called the “68-95-99.7 rule” or “rule of thumb”.

## Who uses the method

Monte Carlo analysis is not only performed by financial professionals, but also by many other companies. It is a decision-making tool, which assumes that each decision will have some impact on the overall risk.

Every person and organization has a different risk tolerance. This makes it very important to calculate the risk of any investment and compare it to an individual’s risk tolerance.

The probability distribution generated by the Monte Carlo model creates a risk map. The picture is an effective way to communicate the results to others (such as superiors or potential investors). Today, anyone with access to a personal computer can design and execute very complex Monte Carlo models.

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