Interactive Finance App

Risk Metrics Explainer

A South African portfolio-risk sandbox for understanding how five core metrics behave under changing assumptions. Adjust the controls, read the interpretation, and compare how each lens frames risk differently in rand terms.

Metrics coveredSharpe, VaR, CVaR, Sortino, Max Drawdown
Use caseSouth African investor education and portfolio risk communication
Best forTurning JSE-style portfolio trade-offs into intuitive discussions
The Sharpe ratio answers: how much return am I earning per unit of risk taken? It divides excess return over a South African cash-rate proxy by total volatility. Higher is better because you are extracting more reward from each unit of variability.
Annual return18.0%
Volatility9.0%
SA cash proxy7.5%

Sharpe ratio

1.17

Acceptable. The return compensates risk reasonably well relative to local cash.

Excess return

10.5%

Return above the local cash-rate baseline.

Below 1.0

Weak. The strategy is not being paid enough for the volatility investors must endure.

1.0 to 2.0

Healthy range for many diversified portfolios and disciplined active strategies.

Above 2.0

Excellent. Strong reward per unit of total risk, though extraordinary values deserve scrutiny.

Why it matters

A flashy JSE-facing return profile can still be inefficient. Sharpe ratio helps separate high-return strategies from genuinely well-compensated strategies.

VaR, or Value at Risk, answers: on a typical bad day, what is the most I should expect to lose? At 95% confidence, it estimates a rand loss threshold that should only be breached on roughly 5% of trading days.
Portfolio valueR1.0m
Daily volatility1.3%
Confidence level95%

Daily VaR

-R21,385

-2.14% of portfolio

Expected breach days

13 days

Approximate number of days per year where losses exceed the threshold.

Historical VaR

Grounded in observed returns and more likely to preserve real stress behaviour.

Parametric VaR

Fast and convenient, but it assumes return distributions behave more cleanly than they usually do in crises.

Blind spot

VaR stops at the threshold. It does not tell you how deep the losses get once the threshold is breached.

Why it matters

VaR is useful for limit-setting and daily loss conversations on rand-denominated portfolios, but it should never be mistaken for a full description of tail risk.

CVaR, also called Expected Shortfall, answers: when losses move beyond my VaR threshold, how bad do they get on average? It focuses explicitly on the tail and is often preferred when discussing severe downside scenarios in South African portfolios.
Portfolio valueR1.0m
Daily volatility1.3%
Tail severity1.5×

VaR 95%

-R21,385

The threshold for a worst typical day.

CVaR

-R32,078

Average loss inside the worst 5% of outcomes.

Close to VaR

Tail losses do not deteriorate dramatically beyond the threshold.

1.3× to 1.6× VaR

Meaningful tail risk that should be priced into capital allocation and stress scenarios.

Above 2× VaR

Severe crisis-period asymmetry. The worst days are materially worse than the headline threshold suggests.

Why it matters

CVaR makes tail losses explicit. It is the metric that tells you whether a bad month in rand terms is merely uncomfortable or potentially existential.

Sortino ratio is a refinement of Sharpe ratio. It only penalises downside volatility, which makes it especially useful when upside swings are strong and frequent. In a South African equity context, it helps separate healthy upside from genuinely painful downside variability.
Annual return15.0%
Total volatility14.0%
Downside volatility6.0%

Sharpe ratio

0.54

Penalises all volatility, even strong upside bursts.

Sortino ratio

1.25

Focuses only on downside deviation.

Why it matters

Strategies with strong upside convexity often look mediocre on Sharpe but materially better on Sortino. That distinction matters when upside volatility in a local mandate is a feature rather than a flaw.

Maximum drawdown measures the deepest peak-to-trough decline experienced by a portfolio. It is often the most psychologically relevant metric because it answers the question investors actually feel: how bad did it get?
Portfolio peakR2.0m
Trough valueR1.6m
Annual return10%

Max drawdown

-18.5%

Peak-to-trough loss.

Calmar ratio

0.54

Annual return divided by maximum drawdown.

Recovery time

2.1 years

Estimated time to recover at the current annual return assumption.

Under 10%

Typically conservative, with lower behavioural pressure on investors.

10% to 25%

Common in equity portfolios and active mandates, but recovery speed matters.

Above 25%

Material capital impairment that requires either exceptional upside or exceptional patience.

Why it matters

A return stream can look attractive until you confront the depth and duration of its worst decline. Drawdown is often where investor conviction breaks, regardless of whether the mandate is local equity, balanced, or income-focused.

Strategy A — SA income sleeve Strategy B — balanced fund tilt Strategy C — small-cap growth