A gap does not have to be filled by trades
Suppose the last trade of the prior session was 100 roubles and the first trade of the next was 84. The difference is −16%. For twenty securities, the change in marked value is −320 roubles before costs. The figures are entirely fictional and do not depict a real issuer. The important point is the absence of required intermediate trades: the market need not execute offers at every price between 100 and 84. A chart mark is therefore not a guaranteed exit opportunity.
Investor.gov warns that a market order does not fix its future execution price, and a stop order may become a market order after activation.[4](#source-cm-orders) An activation level is therefore not automatically a loss limit. A limit condition answers a different question: it restricts the acceptable execution price but may leave the order unfilled. This guide distinguishes trigger condition, acceptable price and available contra-interest; it does not rank order types or offer protection.
Halts have different causes
SEC educational material says a trading halt may, for example, relate to expected material information or a listing-compliance question.[6](#source-cm-halts) That is not the same as an automatic pause after a strong market move. The SEC separately describes market-wide circuit breakers and limits on movements in individual securities.[7](#source-cm-circuits) US thresholds, schedules and procedures do not transfer to a Russian venue. For a particular security, the official notice and applicable rules establish the cause and consequences.
During a pause, the last displayed price may remain unchanged even though participants’ willingness to trade has changed. No new trades do not prove that risk is absent. On resumption, a special price-formation procedure may apply and order availability depends on the system. Do not assume a deferred intention will execute at the old value merely because the screen has not updated. A trading halt and technical unavailability of an application also require different evidence.
What a historical measure leaves outside the frame
The same average volatility can coexist with different distributions of rare jumps. The choice of daily or intraday data, observation period and treatment of corporate actions affects the estimate. A method does not promise a future loss boundary. In particular, do not treat a mechanical price adjustment after a [corporate distribution](/guides/dividends-total-return/) as independent evidence of deteriorating business: comparable series must have the same economic content. The form of a discontinuity alone cannot reliably reveal its cause.
Start with timestamps, the trading calendar, instrument identifier and official reason for missing trades. Then determine whether you are comparing trade prices, quotes or calculated values. The [chart guide](/guides/chart-literacy/) covers series comparability, while [exchange and settlement](/guides/exchange-and-settlement/) separates trading and accounting events. None of these steps is a buy or sell signal; they prevent a technical picture from becoming a promise of limited risk.
Checking the boundaries of historical information
Imagine a series that barely changed for a long time and then stopped updating. That implies neither unchanged value nor an ability to trade at the last mark. First determine whether new observations exist, whether the relevant market is open and whether a restriction applies. No database change and no economic uncertainty are fundamentally different claims.
A second test: a post-corporate-action chart shows a gap while an adjusted series looks continuous. These need not be incompatible descriptions; they may use different comparison units. Check source, adjustment rules and price type before explaining causes. Even after correctly restoring a series, observed gaps describe the past and do not establish the size of the next jump. A promise of maximum loss based on a quiet period adds a guarantee absent from the data.