Simulating investment strategies without risking

Note: this guide is educational and is not financial advice. It describes simulations, not investment recommendations.

Learning to invest with real money is the most expensive school there is. There's an alternative: simulation — or paper trading — testing a strategy on real market data, but with fake orders. The prices are real, the risk is zero. It's a training ground to understand how an approach behaves before exposing a cent. This guide was born building Finanzy, a lab where six bots with different strategies trade on real data without ever placing a real order.

The principle: separate strategy from risk

The value of simulation isn't «making fake money»: it's being able to watch a strategy think. With real money, emotion decides for you; in simulation you can see, with a cool head, what happens when markets fall, what a trend-following rule does against one that goes against it. You learn the reasoning, not just the result.

Six classic approaches compared

The best way to learn is to compare opposite strategies on the same market:

• Concentrated — everything on a single high-conviction stock. Maximum potential, maximum exposure.
• Diversified — the budget spread equally across several stocks, to lower risk.
• Momentum — follows the trend: buys what is rising.
• Contrarian — does the opposite of the crowd: hunts for opportunities where the market overreacted.
• Ethical (ESG) — excludes companies with documented controversies and swaps broad instruments for ethically screened variants.
• Risk parity — weights each holding inversely to its volatility: more capital where it swings less.

There's no absolute «best»: each wins in some markets and loses in others. That's exactly what simulation shows you.

Why the comparison must be honest

A comparison worth anything starts from equal conditions: same basket of stocks, same period, same starting capital. A useful trick is to restart from the same amount at regular intervals (say every month): that way you see which strategy did best on equal terms, without an initial stroke of luck skewing everything after it.

The indicators, in plain words

The strategies lean on a few recurring indicators. RSI: measures whether a stock is recently «overbought» or «oversold». Moving averages: the average price over a period, to read the trend without daily noise. Momentum: how much a stock has risen or fallen over a given number of days. Price/earnings ratio (P/E): how much you pay for every euro of the company's earnings. They're not magic formulas: they're different lenses for looking at the same price.

The disclaimer that really matters

Three things to always keep in mind. First: past results don't predict the future — a strategy that worked yesterday can fail tomorrow. Second: simulation ignores some real-world frictions (fees, taxes, the fact that your order moves the price). Third, the most important: a simulation is a tool to understand, not advice on where to put your money. The value is the reasoning you take away, not the final number.