Why Stock Data Differs Across Websites: Five Things to Compare
Learn to align company identity, accounting scope, periods, units, and formulas across stock data sources. Resolve discrepancies and document the basis used in your analysis.
If stock data differs across websites, first align the subject, accounting scope, period, units, and formula. Even identically labeled items may use different inputs and processing methods. Establish why the difference exists before trying to eliminate it by averaging the figures.
Check that you are comparing the same item
Start your comparison table with company identification details and the relevant shares. Next label whether figures are consolidated or separate, annual or cumulative, and actual or estimated. Finally align currency and amount units. These steps may explain much of the difference. When comparing share prices, also include the trading market, reference time, and whether prices are adjusted. Assuming “the larger site is right” or “I opened it more recently, so it is up to date” before investigating can obscure the data’s actual definition. Even matching figures on two screens do not readily constitute two independent checks if both come from the same provider.
Distinguish original data from processed data
Filed financial statements are suitable for checking company-submitted items and notes, while data services are useful for comparing multiple companies within a consistent framework. The Company Guide user guide separately identifies its sources for share prices, financial data, and consensus data. Services based on the same filings can still differ in account classification or metric calculations. For example, different definitions of net income change the interpretation of per-share metrics. Before changing a value, connect the provider’s definition with the original table title. Do not merge a metric whose definition is unverified with a directly calculated metric under the same name.
Keep discrepancy records for the next update
When you find a difference, record each value, access time, reference period, original location, and verification result. If the issue is a delay in incorporating an amended filing, record when the values began to differ. Do not hide an unresolved discrepancy by arbitrarily choosing one side; exclude it from calculations or present the scopes separately. Fixed definitions for frequently used metrics make it easier to detect changes at the next update. Do not apply those definitions mechanically to every industry, however. Reassess comparability when financial structures differ, as between financial services and manufacturing.
Worked example
Hypothetical example: If screen A shows revenue of 5,000 in units of KRW 100 million and screen B shows 500,000 in units of KRW million, the amounts are the same. Dividing 500,000 by 100 gives 5,000 in units of KRW 100 million. If converting to matching units still leaves a value of 4,600 in units of KRW 100 million, check consolidated versus separate statements and the period. Before calculating this difference as a growth rate, establish whether the figures cover the same scope. Record the selected basis as well as the adopted value in your final comparison table.
What to check
- Are the company, accounting scope, and period identical?
- Have you aligned units and currencies before comparing?
- Have you checked the metric’s denominator and formula?
- Have you avoided treating redistribution from the same provider as independent verification?
Sources and primary materials
This is educational material about research methods. For an actual company decision, verify the filings and primary sources for the relevant period.