Ulcer Index (UI)

Ulcer Index (UI) | Formula, Risk, Performance and Indicator

Ulcer Index charts the course through investment uncertainty, marking not only the depth of potential losses but their duration. This essential guide details the Ulcer Index’s purpose, its calculation method, and how it stands apart from other risk metrics to aid in your financial decision-making.

Risk management is an essential aspect of trading. One of the most valuable indicators for assessing risks is the Ulcer Index. What is the index, and what does it tell you?

The Ulcer Index (UI) is a volatility indicator that measures downside risk in terms of both the depth and duration of price declines. It considers the highest closing price over a given period, typically 14 days, and shows the percentage drawdown a trader can expect from the high over that period.

Key Takeaways

  • The Ulcer Index (UI) is a technical indicator that measures downside risk by assessing the depth and duration of price declines, giving investors insight into potential drawdowns and their ‘stomachability’.
  • A lower Ulcer Index indicates lower drawdown risk, aligning with an investor’s risk tolerance, with values above 10 considered indicative of excessive downside risk.
  • The Ulcer Index is calculated by squaring the percentage drawdowns from peak prices over a set look-back period and taking the square root of the average of these values, thereby quantifying the potential drawdown an investor may face.

What is the Ulcer Index?

Ulcer Index (UI)
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The Ulcer Index (UI) is a risk index that measures the downside risk in financial markets. By examining both the depth and duration of price declines, it gives an indication of market turbulence.

Its value rises when prices retreat farther from recent peaks and falls as they near new highs, thus indicating the expected percentage drawdown from peak levels over a determined period. The name “Ulcer Index” metaphorically relates to what magnitude of drawdown investors might be comfortable enduring without causing themselves “stomach ulcers.”

Below is an image to show how it looks in Amibroker:

Ulcer Index example
Ulcer Index example

Conceived by Peter Martin and Byron McCann in 1987 with mutual funds analysis in mind, the Ulcer Index is distinctively attuned to assessing downward movements rather than all volatility directions like standard deviation does—standard deviation regards upswings and downturns equivalently. In contrast, UI distinctly recognizes just downside risk—the type that potentially inflicts stress or figurative “stomach ulcers” on investors—which makes it exceedingly important for those aiming to keep their portfolios geared towards lower-risk exposure.

The Ulcer Index (UI) is a volatility indicator that measures downside risk in terms of both the depth and duration of price declines. It considers the highest closing price over a given period, typically 14 days, and shows the percentage drawdown a trader can expect from the high over that period. Thus, it increases in value as the price moves farther away from a recent high and falls as the price rises to new highs. Also, the greater the value of the index, the longer it takes for a stock to return to the former high.

The Ulcer Index is a volatility indicator that helps traders and analysts determine risks while trading. However, the index measures volatility only on the downside. First introduced in 1989, the index was designed for assessing mutual funds, which is why the index is primarily based on downside risk — the potential of a security to decline in value due to changing market conditions.

Since mutual funds are created to make money for the investors by only going up in value, the only risks that they face are the downside. The indicator was named Ulcer Index to give investors a clear view of the downside risks to know if they could “stomach” the investment. Many consider the index superior to other ways of calculating risk, such as standard deviation.

What is a good Ulcer Index?

A good Ulcer Index is preferably as low as possible, but a very low number might indicate you have a curve-fitted strategy.

A lower average UI points to lower drawdown risk compared to investments with a higher average UI. Thus, an ulcer index around zero, indicating no downside risk, suggests that prices are steadily rising without significant drawdowns.

By comparing the downside risk of different investments, it enables investors to choose options that best suit their risk profiles. Notably, an Ulcer Index value above 10, though quite rare, can be indicative of excessive downside risk.

Thus, the Ulcer Index serves as a compass, guiding investors through the turbulent waters of investment risk and helping them shape their investment strategy.

What is the Ulcer Index formula?

Ulcer Index Simplified

The Ulcer Index formula is a measure of downside risk that takes into account both the depth and duration of drawdowns. It’s calculated as the square root of the average squared drawdowns over a specified period. The formula is:

Ulcer Index = √(1/N * Σ (Ri – L)^2)


  • Ri is the percentage drawdown for period i
  • L is the percentage drawdown threshold (typically 0)
  • N is the number of periods

How do you calculate the Ulcer Index Formula?

You calculate the Ulcer Index by following a 3-step calculation. The three steps are given as follows:

Step 1: Getting the Percentage Drawdown

Percentage Drawdown = [(Close – 14-period Highest Close)/14-period Highest Close] x 100

Step 2: Getting the Squared Average

Squared Average = (14-period Sum of Squared Percentage Drawdown)/14

Step 3: Getting the Ulcer Index

Ulcer Index = Square Root of Squared Average

To fully understand the Ulcer Index, it’s essential to comprehend its formula. The process begins with calculating the percentage drawdown by comparing each period’s closing price against the highest closing price during a predefined look-back window, often set at 14 days. These percentage drawdowns are then squared and an average of these squares is determined, referred to as the Squared Average. To complete the calculation, one must extract the square root from this Squared Average, which yields the Ulcer Index.

The standard time frame for assessment is typically 14 periods. This can be tailored according to individual preference. The relevant high price point for computation shifts depending on how long or short you set your look-back interval, something that may extend up to 50 days if assessing more extended periods of decline in prices. Ultimately, what the Ulcer Index offers is a measure of potential percentage declines that investors might face over their chosen period. It serves as an insightful metric on downside risk exposure.

Note that the price high used in the Ulcer Index calculation is determined by adjusting the look-back period. Thus, a 14-day Ulcer Index measures the decline from the highest close in the past 14 days, while a 50-day Ulcer Index measures the decline from the 50-day highest close. A longer look-back period offers a more accurate representation of the long-term price declines they may face. Conversely, a shorter-term look-back period shows potential short-term volatility.

How do you calculate the Ulcer Index?

To calculate the ulcer index, you must:

  • Determine each period’s percentage drawdown by comparing the closing price to the highest closing price over a specified retrospective period.
  • Square these individual percentage drawdowns.
  • Add up all of the squared percentage drawdowns across what is typically a 14-period span.
  • Find out what your Squared Average is by dividing this total sum by your chosen number of periods, which in our example is 14.

In order to get to the final value known as the Ulcer Index, take the square root of that Squared Average. This index reflects an expected measure of potential downside risk in terms of average percent fall from recent peaks during that given look-back timeframe. More specifically, it quantifies mean risk intensity based on how much prices have retreated from their previous highs within this interval.

Who invented the Ulcer Index?

The Ulcer Index was developed by Peter Martin and Byron McCann for analyzing mutual funds. The indicator was created in 1987, but Martin and McCann first published it in their 1989 book, The Investor’s Guide to Fidelity Funds.

The indicator was designed to measure only the downside risk, not the overall volatility that other volatility indicators, such as the standard deviation measure. Martin’s and McCann’s intention was to create a way to measure the downside risk, which causes stress and stomach ulcers, as the index’s name suggests.

What are the primary factors influencing the Ulcer Index?

Ulcer Index Factors

The primary factors influencing the Ulcer Index are:

  • The severity and length of drawdowns or price declines within an investment portfolio. Notably, the more substantial a drawdown is, the heavier its influence.
  • The period being considered to determine percentage drawdown
  • What threshold is set for considering a price decline as a true ‘drawdown’

These components play crucial roles in formulating ulcer index values.

External factors such as prevailing market conditions and asset liquidity don’t directly enter into the equation but do shape how one interprets Ulcer Index data. How quickly an investment bounces back from downturns can affect perceptions of portfolio risk using this measure.

In essence, individual definitions of what constitutes risk are mirrored by choosing parameters like look-back periods and thresholds for declines when calculating the ulcer index value. These decisions inherently tailor it to reflect personal risk tolerances.

What are the common applications of the Ulcer Index?

The common applications of the Ulcer Index is investment analysis and strategy for assessing mutual funds and other securities. This statistical tool evaluates them based on their exposure to downside risk, specifically measuring the depth and duration of drawdowns in value. It provides a foundation for the Ulcer Performance Index (UPI), also known as the Martin Ratio, which offers insights into risk-adjusted returns.

For investors seeking to minimize exposure to high volatility investments while focusing on those with an upward trend, the Ulcer Index is instrumental during scans by filtering out assets that present substantial downside risks. It’s especially beneficial for long-term investors due to its focus on sustained periods of declining asset values.

Financial experts utilize this measure when contrasting the relative volatility of various instruments including fidelity funds. They aim at choosing ones with lower average UI readings indicating less severe potential declines hence implying reduced drawdown risks.

What role does the Ulcer Index play in trading analysis?

The Ulcer Index plays a minor role in trading analysis because it’s more geared toward long-term investments than short-term trading.

This metric quantifies downside risk by evaluating both the severity and longevity of price declines, which is essential for gauging the associated potential risk with an investment vehicle. It reveals how much percentage drawdown traders might anticipate over a certain timeframe, commonly utilizing a 14-day window to gauge short-term exposure to risk.

An upward trajectory in the Ulcer Index often reflects an extended period of falling prices for a security, indicating possible prolonged losses. Such information can be pivotal for traders contemplating whether they should liquidate their position to mitigate Depreciation.

In contrast, when values on the Ulcer Index approach or remain at zero levels, it Implies consistent positive performance from a security—information that could prompt traders to initiate new positions based on anticipated gains.

Overall, through its insights into market volatility and potential downturns in securities’ value.

The University of Illinois offers invaluable guidance which assists traders in their strategic decision-making process regarding investments.

How does the Ulcer Index compare to other risk metrics?

The Ulcer Index stands out among risk assessment tools because it focuses solely on downside risk. This index differs from metrics such as the standard deviation that regard price fluctuations in both directions equally. Instead, it zeros in only on drops in prices. Thus, it presents a more targeted measure of potential dips an investor might encounter, which is especially pertinent for those mainly concerned with how declines could negatively impact their investment portfolio.

On the other hand, the Sharpe ratio takes into account overall volatility by using standard deviation to determine a normalized return metric adjusted for risk. Unlike the Ulcer Index, This does not specifically factor in penalties for downward movements. The unique emphasis of the Ulcer Index on downside risks significantly shifts how one evaluates investment danger and returns that are adjusted based on these risks—particularly within strategies designed to minimize significant losses.

What are the limitations of the Ulcer Index?

The limitations are mainly related to the index being best suited for long-term investments. It is tailored mainly for mutual funds and investments with a long-only approach and concentrates solely on assessing the potential of downside risk.

This focus renders it less applicable to various investment vehicles or strategies that involve more complex trading methods. For those engaged in short-term trading practices, its reliance on historical data may delay responsiveness to swift fluctuations within the financial markets.

The index’s susceptibility to changes in the look-back period can serve as a drawback since adjusting this timeframe might lead to significant shifts in findings and cause an inconsistency regarding risk exposure evaluations. Consequently, although adept at evaluating downside risk associated with investments, prudent application of the Ulcer Index requires it be combined with additional measures of risk analysis tools while bearing its inherent limitations well in mind.

How can traders utilize the Ulcer Index to manage risk?

Traders can utilize the Ulcer Index to calibrate the period setting of this indicator to fit their own trading approach; they can fine-tune their strategies accordingly.

By opting for assets with a relatively modest Ulcer Index rating, traders are choosing those with less severe depth and duration in terms of price drops — indicating lower downside risk. The tool is equally useful when determining position sizing or implementing stop-loss orders to curtail possible declines in value. Consequently, within the often volatile financial markets landscape, the Ulcer Index emerges as a critical navigational aid for traders.

Are there different variations or interpretations of the Ulcer Index?

Modifying the retrospective analysis timeframe is one such variation. For example, an Ulcer Index with a 14-day horizon evaluates drops from the peak over that period, while an index employing a 50-day span looks back to measure declines from highs within those fifty days. Selecting different periods for evaluation allows for results that more closely meet investor goals by providing risk assessments tailored to their individual requirements.

One may encounter an alternative usage of this metric known as the Ulcer Performance Index (UPI), or simply Martin Ratio. This approach offers a twist on traditional methods by incorporating total returns into calculations relative to downside risk rather than using standard deviation—an element typically factored into assessing volatility and return variability—to arrive at risk-adjusted outcomes.

The UPI accomplishes this by deducting the yield of any perceived ‘risk-free’ investment from your aggregate gain before dividing it by its own counterpart—the Ulcer Index—with objectives set firmly on distinguishing investments based on superior risk-adjusted performance metrics.

Consequently, due to its inherent versatility, investors are able to utilize adjustments within the parameters of the Ulcer Index framework—tailoring it precisely towards satisfying their respective investing strategies and necessities in regards to exposure management.

What does the Ulcer Index tell you?

Here is what the Ulcer Index tells you according to Peter Martin and Byron McCann::

Ulcer Index measures the depth and duration of percentage drawdowns in price from earlier highs. The greater a drawdown in value, and the longer it takes to recover to earlier highs, the higher the UI. Technically, it is the square root of the mean of the squared percentage drawdowns in value. The squaring effect penalizes large drawdowns proportionately more than small drawdowns.

Most analysts recommend using the index as a measure of risk in any situation where the standard deviation (SD) can be used. As a statistical measure, you can compare the Ulcer Index values of different assets to determine relative risk, and the index tends to work well with weekly data.

You can also chart the Ulcer Index over time and use it as a kind of technical analysis indicator to show stocks that are going into an ulcer-forming territory. The value you designate as your ulcer-forming territory is up to you.

How do financial professionals use the Ulcer Index in their decision-making?

Financial experts employ the Ulcer Index in various ways to inform their investment choices, considering not just the returns but also adjusting for risk. This enables them to modify their portfolios by steering clear of excessively fluctuating investments. The key role of the Ulcer Index is to pinpoint investment opportunities that present both low volatility and substantial return potential, setting itself apart from other risk metrics such as standard deviation or beta coefficient.

Investors make use of the Ulcer Performance Index (UPI) – which integrates the Ulcer Index – for evaluating risk-adjusted returns. This involves a consideration of both loss magnitude and duration within a portfolio. Through computation of the Ulfer index, financial professionals are equipped with insights necessary for guiding asset allocation and strategies tailored towards managing risks effectively.

Thus, it’s evident that within financial management spheres, the ulcer performance index is indispensable in aiding finance professionals when orchestrating portfolio management and executing savvy investment resolutions.

What are the pros and cons of the Ulcer Index?

The pros of the Ulcer Index include:

  • Not only evaluates returns but also assesses risk, offering a fuller picture of how portfolios perform To more traditional benchmarks such as the standard deviation.
  • Recognizes losses’ psychological impact on investors – an aspect especially relevant for those with long-term investment horizons.
  • It assists investors by pinpointing potentially overly volatile or high-risk investments for their portfolios, which aids them in making more enlightened choices.

These are the drawbacks to consider regarding the Ulcer Index:

  • It is predominantly tailored towards mutual funds and positions with a long orientation. Thus, it may not align well with every kind of trading strategy or investment category.
  • When it comes to short-duration trading activities, its effectiveness diminishes because it relies upon historical data over a specified period and might lag behind quick market shifts.
  • The level of sensitivity concerning its look-back duration can yield variable risk assessments.


The Ulcer Index measures how severe and how long price drops might be, giving a clue about future potential losses. It serves multiple purposes, such as evaluating investment vehicles, comparing the potential for loss across different alternatives, and assessing performance on a risk-adjusted basis.

Frequently Asked Questions

What is the Ulcer Index in share market?

The Ulcer Index evaluates the downside risk by scrutinizing both how deep and how long prices fall below recent peaks. This index escalates when share prices drop significantly away from recent highs and diminishes when shares recover to establish new highs.

What is the importance of Ulcer Index?

The Ulcer Index plays an important role by quantifying the downside risk associated with a stock, reflecting its utmost potential to decrease in value amid fluctuating market scenarios. This metric is instrumental for investors looking to evaluate and handle the risk of their equity holdings potentially losing value.

How do you interpret Ulcer Index?

You interpret the Ulcer Index by studying and quantifying the intensity and longevity of price declines from previous peaks by calculating percentage drawdowns. An increase in both the magnitude of these downturns in value and the time required for a recovery back to former high points results in a higher UI score.

How is the Ulcer Index calculated?

The Ulcer Index is calculated by measuring the depth and duration of drawdowns in price from previous peaks by first determining the percentage drop, then squaring these percentages. These squared figures are averaged across a designated retrospective time frame, after which the square root of this average is computed to obtain the final value.

How does the Ulcer Index compare to other risk metrics?

The Ulcer Index focuses solely on downside risk while other look at both opside and downside risks.

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