Top Stock Gainers of the Day: What a One-Day Rise Measures and What It Does Not Promise

The top gainers list is not a selection of the best stocks but a sort: every traded share is ranked by its price change over the trading day, from the largest gain downwards. There is exactly one criterion here, and it is mechanical — the relative change in price from the previous close to the current price. So the top of the list is occupied by whatever saw the balance of supply and demand shift the most today specifically, not by whatever is more reliable, cheaper or more promising than the rest.

What exactly is measured

The daily change is the ratio of the current price to the previous closing price, expressed as a percentage. Only the price of trades goes into the calculation. Nothing that usually determines the result of owning a share goes into it: not the dividend paid, not the size of the company, not the volume of trades executed, not the number of shares actually available to the market.

This leads to the first practical consequence. If a stock has passed its ex-dividend date, the price falls on that day by the amount of the payout, and the stock drops to the tail of the ranking, even though the holder has suffered no loss at all. The reverse also happens: on technical events the price moves without any news about the business. That is why a ranking by daily change should be read alongside the dividend calendar and the news feed — otherwise some of the moves look inexplicable.

Why the top of the list changes every day

The daily change is a figure with a very short memory. It resets every session. A ranking built on such a criterion has no inertia: a stock reaches the top because of an event on a particular day and leaves the list the very next day if that event had no follow-through.

What most often carries a share to the top:

• the release of results or guidance that diverged from market expectations — see the reports section;
• a corporate event: a declared payout, a share buyback, a reorganisation, a conversion of preferred shares;
• sector news or a change in an external price — commodities, the currency, the interest rate;
• a move in an illiquid stock, where an order flow that is small in money terms pushes the price a long way because there is almost no supply in the order book.

The last item is the main trap of this list. The smaller the free float and the average daily turnover, the easier it is for a stock to take the top line. As a result, the share of little-known names among the top gainers is systematically higher than their share of the market's capitalisation. This is not the sign of a discovery; it is a property of the metric itself.

What a one-day rise cannot tell you

More specifically, this criterion does not allow you to judge:

• the pace of the business. A day's rise in the price and the CAGR of revenue or profit are figures of a different nature and a different horizon; the daily change says nothing about the sustainable growth rate;
• cheapness. A stock may be rising and still be expensive on its multiples, or it may be rising precisely because it was cheap. The ranking does not distinguish between these cases — telling them apart takes no data and no data for the specific stock;
• the type of stock. A "top gainer of the day" and a growth stock are different concepts that share nothing but a word. The first is a fact about one session, the second is a characteristic of the business model and of expectations; the difference between these grounds for buying is examined in the piece on growth and value stocks;
• the benefit to the holder. The price may rise while the shareholder's stake in the company shrinks: that is how a follow-on share issue works, and, in the opposite direction, so does a share cancellation.

A separate caveat concerns the values themselves. While the session is under way, the change shown in the list is provisional and reshuffles the rows during the day; it becomes final after the close. How often this particular table is recalculated is determined by the platform's data update schedule — and that is something to check in the description of the section rather than to guess from the look of the figures.

How to read the list below

Step 1. Look not at the position in the ranking but at whether you recognise the name. A large, liquid stock at the top is usually the result of substantive news. An unfamiliar name is more often the result of a thin market.

Step 2. Find the cause. Open the instrument's page and the events related to it: {{instrument:SBER}} is an example of what such a page looks like, with financial reports, payouts and the corporate calendar sitting next to the price. If the cause is to be found neither in the news nor in the events calendar, that is important information in itself.

Step 3. Compare with the alternative, not with zero. A move of several per cent in a day seems large until you set it against the return the debt market offers without price risk — see the OFZ section and the simple yield to maturity.

Step 4. Do not make the decision from the ranking. The list of top gainers is a tool for finding questions, not answers. It shows where something happened today. What exactly happened, and whether it matters to you, is settled outside the table: in the full list of stocks, in the financial statements and in the glossary, if you have come across an unfamiliar word.

The mirror metric — the one-day decline and its limitations — is worth reading together with this one: the errors of interpretation there are the same, only more visible.