Investment scenario analysis

Investment scenario analysis is the practice of running two or more investment strategies side by side using the same starting balance, the same horizon, and the same set of explicit assumptions, then comparing the final outcomes net of fees and dividends. It’s how you tell whether a “high-return” fund actually beats a “boring” index fund once the real-world friction is included.

Why side-by-side comparison matters

A fund’s headline return number is rarely the number that ends up in your account. Fees compound against you, dividends compound for you (only if reinvested), and contribution timing can move the result by tens of thousands of dollars over a long horizon. Looking at one strategy in isolation tells you nothing about whether it’s a good choice — you need a comparison.

Scenario analysis enforces a fair comparison: the same money, the same horizon, the same underlying market assumptions where they overlap, and only the variables that genuinely differ between the strategies are varied.

What gets compared

A meaningful comparison includes:

• Final value. What you end with after the horizon.
• Total contributed. Initial deposit plus all recurring contributions.
• Total fees. A separate line — fees disappear from your balance forever.
• Total dividends. Tracked explicitly, with reinvestment as a separate switch.
• Annualised return. The compound rate that turns the starting balance into the final value over the horizon — this is the apples-to-apples comparison number.

The strategy with the highest final value is not always the “best” — it might require contributions you can’t sustain, or carry volatility you can’t tolerate. But the model gives you a clean, numbers-first starting point.

What it does not tell you

Investment scenario analysis is a deterministic projection. It does not model:

• Volatility. Markets do not deliver a smooth annual return. Two strategies with the same expected return can have very different paths.
• Sequence-of-returns risk. When returns occur in a different order — early losses vs late losses — the same average return produces different final values, especially with contributions or withdrawals.
• Tax consequences. Tax treatment of dividends, capital gains, and contributions can change which strategy wins.
• Behaviour. The “best” strategy on paper isn’t best if you abandon it during a downturn.

For these reasons, scenario analysis is best used as a first filter: rule out strategies that don’t even win on paper, focus on the ones that do, and then evaluate them on dimensions the model can’t capture.