How stock seasonality is calculated

Seasonality asks whether a stock has tended to rise or fall in the same part of the calendar, year after year. Flash Finance measures it from end-of-day prices for every stock in the price database, and for the Nifty 50.

Periods and returns

• Month and quarter: calendar months and quarters.
• Week of the month: week 1 runs from the 1st to the first Friday, and each later week runs Saturday to Friday, up to a fifth week. So "July, week 3" is the same calendar slot every year.
• A period's return is its last close compared with the last close of the period immediately before it. If the stock did not trade in that previous period, no return is recorded, so a suspension cannot produce a fake multi-month move.
• Returns outside sanity limits (below −95% or above +400% for a month, for example) are left out as data errors, not clipped.
• The period in progress is shown as "so far" and never counted in the statistics.

Statistics per stock

For each stock and period: the number of years it rose and fell, its win rate, its average and median return, and its best and worst year.

Top-25 and Bottom-25

• Ranking by consistency, with a penalty for short records. Stocks are ranked by the Wilson lower bound of their rise rate (Top-25) or fall rate (Bottom-25), a one-sided 95% bound. It ranks 17 rises in 18 years above 10 in 10, where a plain win rate would do the opposite. The average return must also point the same way.
• History required: at least 10 years for months and quarters. Weeks are pooled across months (every week 3 of every month counts), and need at least 96 observations, about eight years.
• Walk-forward. The list for a period uses only years before it: the July 2026 ranking knows nothing about July 2026. So the past lists on the page are a fair record of how such picks did.
• Current lists include only stocks that traded in the last 21 days.

The track record, and how to read it

Each past list is compared with the Nifty 50 and with the median stock over the same period. The Top-25 table compares the picks' average return with the median stock. A few large winners lift an average more than a median, so this comparison flatters the picks; compare their median column as well. The Bottom-25 record compares the median pick with the median stock.

Limits

A calendar pattern can come from a few unusual years, and many stocks are tested at once, so some will look seasonal by chance. Seasonality describes the past; it is not a forecast.