Investing in Value at Risk: Complete Guide 2025

Mastery of risk management is an essential condition for successful investments in 2025, especially in an uncertain economic environment and with markets that can sometimes be highly volatile. Among the tools available to investors, the Value at Risk (VaR) remains an indispensable indicator for anticipating potential losses and structuring one’s portfolio accordingly. This article delves into the intricacies of VaR, detailing its foundations, its practical utility, and its application to the real case of ValiRx plc (VAL.L), a biotechnology company listed on the London Stock Exchange.

Introduction to Value at Risk (VaR)

The Value at Risk, or VaR, refers to a statistical measure that allows evaluating the maximum potential loss of an investment over a given period and for a predefined confidence level. Widely used in financial circles, it is equally relevant for individual and professional investors who wish to assess the resilience of their portfolio against market volatility.

Exact Definition of VaR

In summary, VaR answers the following question: « What is the maximum loss that a portfolio could incur, with a given probability, over a fixed time horizon? » Let's take an example: a daily VaR at 95% of €1,000 means there is only a 5% chance that your daily loss will exceed this amount.

VaR thus enables setting risk limits, comparing assets, or adjusting hedging strategies. However, it should not be interpreted as a guarantee, as it does not account for extreme circumstances, known as « fat tails » in the distribution of returns, which could lead to much larger losses than indicated by the VaR.

The Major Calculation Methods of VaR

  • Historical approach: It relies on the history of returns to estimate the distribution of losses. Easy to implement, this method assumes that the past will repeat itself.
  • Parametric modeling: It assumes that returns follow a normal distribution and calculates the VaR based on the observed standard deviation and mean.
  • Monte Carlo simulations: This method generates a large number of market scenarios to estimate the distribution of potential losses, offering flexibility and precision.

Each method has its advantages and limitations: relevance depends on the type of assets analyzed, the depth of historical data available, and the user's objectives.

Why is VaR Indispensable in 2025?

In a more complex financial universe, the Value at Risk emerges as a central tool for:

  • Evaluating and comparing the risk associated with different investments
  • Setting loss tolerance thresholds
  • Optimizing portfolio diversification
  • Enhancing active management discipline

In 2025, marked by technological innovations, geopolitical tensions, and high volatility in certain segments, the ability to anticipate probable losses through Value at Risk (VaR) is all the more valuable as investors need both returns and security.

The Key Components of VaR

  • Historical performance data: Past data on assets serve as the basis for analyzing the distribution of returns.
  • Volatility: The higher the volatility of an asset, the greater the risk of losing a significant sum over a short period.
  • Correlation: The concurrent evolution of several assets within a portfolio can amplify or mitigate overall risk.
  • Confidence level: VaR depends on the chosen confidence level (95%, 99%, etc.), the higher it is, the greater the estimated VaR will be.

It is essential to note that in cases of poor liquidity, VaR may underestimate the actual risk, especially for low market capitalization stocks.

Case Study: Applying VaR to ValiRx plc (VAL.L)

Introduction to ValiRx plc

ValiRx plc is a British biotechnology company listed on the AIM market of the London Stock Exchange, specializing in the development of innovative therapies against cancer and women's health-related diseases. Its modest size makes it a high-risk micro-cap, which is ideal for illustrating the relevance of a VaR analysis on this type of asset.

Key Financial Data of ValiRx plc as of November 11, 2025

  • Share price: 0.60 GBX (approximately €0.0069)
    • Market capitalization: approximately £2.25 million (equivalent to nearly €2.6 million)
  • Number of shares outstanding: 374,349,000
  • P/E Ratio: -0.41 (the company is loss-making)
  • Beta: 0.59 (positive)
  • Dividend: 0.00 (no payment)
  • Net income TTM: -£5.71 million

Interpretation of Data and Risk on ValiRx

The risk profile of ValiRx plc is particularly marked by its lack of profitability (negative net income, negative P/E ratio) and its very low market capitalization. The low per-share price and recent dilution suggest notable volatility, despite a beta below 1 (0.59), which suggests that the stock is slightly less sensitive than the market as a whole.

Contrary to a common misconception, a positive beta below 1 does not imply countercyclical behavior: ValiRx follows the general trend of the market but with moderate amplitude. However, underlying high volatility may characterize this type of micro-cap, especially during share issuance or strategic development announcements.

Liquidity, Volume, and Impact on VaR

The real liquidity of ValiRx is low: daily volumes do not exceed a few million shares, exposing investors to a “gap” risk (price spread in case of large orders or major announcements). This increases the potential risk of losses exceeding the VaR calculated by classical models ("liquidity risk").

Sectorial evolution and catalysts

In autumn 2025, ValiRx announces a new licensing agreement worth up to 16 million pounds sterling, including royalties, an evolution likely to impact future valuation and the associated risk perception of the stock. However, no immediate effect has been observed on profitability or cash flow, the company still showing losses over several consecutive periods.

A prudent investor relying on VaR will therefore take into account the speculative nature of such a value while remaining attentive to the specific volatility of the biotechnology sector, where results can differ drastically from one quarter to another.

The limits of VaR: beyond statistics

Even when correctly calculated, VaR has its limitations:

  • Failure to account for extreme losses: VaR does not model rare but catastrophic events ("tail events").
  • Assumptions about the distribution of returns: Parametric models often assume normality which does not reflect the reality of highly speculative markets like micro-cap biotech.
  • Liquidity effect: A VaR calculation based on historical data of low volume risks underestimating the real loss during a wave of massive sales.
  • Model risk: A poor selection of parameters completely distorts the conclusions.

In the case of ValiRx, these limitations are further exacerbated by the modest size of the company, the shallow market depth, and the uncertainty surrounding the future valuation of its patents and licenses.

Investment strategies around VaR in 2025

Diversification and risk mitigation

The first rule to mitigate the risk identified by VaR is diversification. By allocating a limited portion of the portfolio to micro-caps like ValiRx, while favoring assets with lower volatility (bonds, blue chips, diversified ETFs), one reduces the probability that the maximum calculated loss becomes catastrophic for the entire portfolio.

Furthermore, for this type of highly volatile and illiquid value, it is recommended to adopt an active stop-loss management: continuous monitoring of VaR and setting automatic sell limits reduce unexpected losses.

Active management and hedging

Professional investors do not hesitate to adjust the size of their position according to the daily evolution of VaR. In case of increased risk, it becomes prudent to reduce exposure. Additionally, derivatives such as put options or futures contracts can serve as additional hedges, although their availability is limited in the case of micro-cap stocks.

It is important to note that by 2025, the regulatory environment and increased transparency of AIM markets allow for better risk assessment, while requiring more management discipline and daily monitoring of key indicators (stock prices, volume, company announcements, and industry news).

Practical Tips for Applying VaR as an Individual Investor

  • Regularly update your price and volume data so that your VaR calculation reflects market reality.
  • Systematically integrate liquidity into your stress test scenarios.
  • Never invest more than you are willing to lose on micro-cap stocks with low visibility and high volatility.
  • Multiply time horizons: Compare VaR over one day, one week, and one month to better understand the potential magnitude of movements in your portfolio.
  • Analyze sector trends: An announcement of a partnership, funding round, or licensing agreement can abruptly change volatility and thus the VaR of the following days.
  • Maintain strict discipline on your stop-losses and maximum acceptable loss targets.

Finally, do not forget that the goal of VaR is to limit unpleasant surprises and structure your investment method: it complements but does not replace rigorous fundamental analysis of each stock.

Conclusion: Why VaR Remains Essential for Investing in 2025

The Value at Risk has become a global reference for anticipating, measuring, and containing the maximum potential loss in a context of persistent uncertainty. The case of ValiRx plc is exemplary: a promising but still loss-making company exposed to sometimes extreme fluctuations, its real risk often exceeds what a simple volatility ratio or beta suggests.

The informed investor, whether trading in biotech micro-caps or diversified portfolios, must integrate VaR into their analysis grid, notably:

  • to define stop-loss levels
  • to make sectoral choices
  • to set priorities for diversification
  • to raise awareness about the reality of extreme risks

In 2025, more than ever, rational risk management becomes the differentiating factor between capital preservation and pursuit of performance.