Psychology

5 Trading Superstitions: Myth or Fact?

Astron Team · 09/24/2026 · 4 min read

Every financial market carries a handful of popular beliefs repeated generation after generation of traders, some with a bit of grounding in collective behavior, others pure confirmation bias — the tendency to remember only the times the belief worked and forget every time it didn't. Let's put five of the most common ones to the test.

1. Round numbers are always support or resistance

There's some real basis here: since many market participants place orders at round numbers (R$ 50.00, R$ 100.00, and so on), those levels tend to concentrate more orders than an arbitrary value like R$ 49.73. But treating this as an automatic rule is a stretch — price breaks round numbers all the time, especially during strong trending moves. Verdict: partly true, but no guarantee at all.

2. After five losses in a row, the next trade has to be a win

This is a version of what's called the gambler's fallacy: the idea that after a streak of results on one side, the opposite result becomes more due. Statistically, if each trade is independent of the previous one — which is usually the case in strategies with no explicit historical dependency — the probability of winning the next trade doesn't change because of prior losses. Verdict: myth, and a dangerous one, because it leads people to increase risk right after a bad streak, hoping to make up for it.

3. Monday is reversal day, Friday is continuation day

Academic studies on calendar effects do exist, and historically some markets have shown weak statistical patterns tied to days of the week during specific periods. But these patterns, when they exist, tend to be small, unstable over time, and insufficient to support a strategy on their own. Verdict: mostly a myth in practice — the effect, when it existed, was too small and too inconsistent to be a reliable rule today.

4. This indicator never fails, I just need to find the right settings

No technical indicator — RSI, MACD, moving averages, or any other — has a 100% win rate in any market, because all of them are calculated from the price itself, which already embeds the unpredictability of participants' collective behavior. Repeatedly tweaking parameters until you find a setting that got everything right on a specific historical stretch is usually a symptom of overfitting to the past, not a generalizable magic formula for the future. Verdict: myth. Every indicator fails sometimes, and accepting that from the start is part of any healthy strategy.

5. If a lot of people are talking about an asset, it's time to buy

When an asset becomes a widespread topic — on social media, in casual conversations — this generally means the price move has already advanced quite a bit before turning into popular news. Historically, spikes in general public interest tend to coincide with advanced stages of a move, not with its beginning. Verdict: mostly a myth — late popularity tends to be a signal of attention, not an entry opportunity.

What these superstitions have in common

Four of the five beliefs analyzed here survive because the human brain is good at noticing and remembering the cases where they worked and quickly forgetting the cases where they didn't — the already mentioned confirmation bias. The only one with some consistent statistical basis (round numbers concentrating orders) is still far from being a reliable rule on its own.

How to handle popular market beliefs

A practical way to test any belief before incorporating it into your strategy is to look at a reasonable history of charts and objectively count how many times it actually held up versus how many times it didn't — instead of relying only on memory or on what you've heard from other traders. This simple exercise alone debunks a good part of the most widespread superstitions.

Why it's worth questioning these beliefs

Accepting a superstition without testing it costs more than it seems: every belief carries, embedded in it, a risk decision — increasing position size, entering at a specific time, blindly trusting an indicator. Replacing those decisions with a simple test, done calmly before any real trade, is what separates a routine based on discipline from one based on tradition repeated without verification.

Practical conclusion

Popular beliefs are part of the culture of any market, but real risk decisions deserve more than oral tradition. Testing, counting results, and being wary of any rule that promises a guaranteed win is the safest way to keep a superstition from replacing real analysis — always remembering that no rule, tested or not, eliminates the risk of loss in trading.