What it means
A rising market can be described as a bull market when its advance is substantial and sustained. The label usually refers to a broad stock market or index, not every individual stock. A commonly used convention is a rise of at least 20% from a recent low, although there is no universal rule for the starting date or the length of time the rise must last.
A bull market describes prices that have already risen; it does not establish what prices will do next. Individual stocks may fall while the index rises, and an index can have setbacks during a longer advance. The opposite label, bear market, generally describes a sustained decline.
How it is calculated
The common 20% test measures the percentage change from an index low to a later index level:
Rise (%) = [(later index level − reference low) / reference low] × 100
- Later index level: the index value being assessed, measured in index points.
- Reference low: an earlier low for the same index, also measured in index points.
- Rise (%): the change relative to that low, expressed as a percentage.
Both levels must come from the same index. The formula measures a price-index change if the index excludes reinvested dividends; a total-return index includes them under its own methodology. Neither calculation proves that every constituent stock rose. Identifying a particular bull market also requires a choice of reference low and a convention for when the period ends.
Worked example
Suppose a hypothetical stock index reaches a low of 1,000 points and later stands at 1,220 points.
- Subtract the low: 1,220 − 1,000 = 220 points.
- Divide by the low: 220 ÷ 1,000 = 0.22.
- Convert to a percentage: 0.22 × 100 = 22%.
The index exceeds the commonly used 20% threshold. Under that convention, an observer could describe the advance as a bull market. The calculation says nothing about how long the rise will last. If one stock in the index fell over the same period, the index result would not change that stock's individual return into a gain.
Why it matters before you trade
A market-wide advance provides context, but it is not a measure of an order's execution costs or a basket's risk. Before placing an order, a pre-trade check can examine the stock's liquidity, estimated bid-ask spread, expected market impact and volatility. A large order relative to normal daily volume may face different execution conditions from a small one, regardless of the market label.
For a basket, concentration matters too. Several stocks may share exposure to the same sector or country even when their tickers differ. An upward index trend does not remove the possibility of losses, gaps or partial fills. Market context and trade-specific conditions answer different questions.
How PreTrAIde uses it
The product facts do not state that PreTrAIde calculates or assigns a bull-market label. Instead, its pre-trade analysis evaluates a user-built stock basket before an order is placed. Its quantitative layer estimates measures including spread, participation in daily volume, market impact, daily volatility and one-day 95% value at risk; it also assesses portfolio breakdowns and concentration.
PreTrAIde returns a GO, NO-GO or MODIFY verdict for the basket and each line, with reasoning, risk assessment and a suggested execution strategy. These verdicts are decision support, not recommendations. The stated success probability is a model estimate, not a forecast of returns or a guarantee. Users place any trades themselves through their own broker.
Common mistakes
- Treating 20% as an official rule. It is a convention; definitions and chosen reference lows can differ.
- Assuming every stock participates. An index can rise while some of its constituents decline.
- Confusing an index gain with a trade return. Entry price, dividends, fees and execution costs affect an investor's result.
- Treating the label as a signal about tomorrow. It describes an observed advance, not a reliable forecast or a substitute for checking a specific order.