J-Quants Adjusted Prices and Stock Splits

In a fictional two-for-one split, a price moving from 2,000 to 1,000 alongside doubled shares does not itself imply a halving of holding value. Separate unit changes from market returns.

A large decline is not automatically a split. Verify the event and the supplied adjustment basis instead of judging a series by how smooth it looks.

J-Quants offers raw and adjusted historical stock prices. Choose a feature basis explicitly and retain the acquisition and transformation record for that series.

An adjusted price is not automatically a total-return series with dividends reinvested. Confirm adjustment coverage and state whether the experiment measures prices alone or includes cash distributions.

Range and open-to-close calculations are sensitive to the basis of every price field. An unnoticed mix of raw opens and adjusted closes can create a ratio that does not describe one trading session.

For a fictional split-spanning range study, align all OHLC fields. Check volume treatment too before multiplying a transformed price by an unchanged share count.

An account model must handle quantities, cash and execution prices consistently. Multiplying a fixed quantity by retrospectively adjusted historical prices is not automatically valid holding accounting.

If a fictional position changes from 100 shares to 200, reconcile values around the event. A simplified model that omits corporate-action accounting needs an explicit interpretation boundary.

KabuForge's public course states a particular price and accounting basis. Switching series requires reviewing quantity scheduling and valuation rather than expecting the original result.

Do not extend a reference course into a universal corporate-action guarantee. Treat a changed basis as a separate experiment and compare its receipt and account rules.

Continue with J-Quants and Point-in-Time Research, Listed Issues and Market Segments, Financial Data: Periods and Units to connect input definitions, availability and evaluation. All numerical and company examples in this article are fictional teaching examples. For real input, prioritize the documentation for your version and your own acquisition and execution records.

Check the official KabuForge GUI research course for documented workflow scope, and JPX: J-Quants datasets, J-Quants: official V2 column definitions for provider documentation or current official implementation. Confirm exact units and access limits against the applicable official specification and contract. General research design guidance does not establish that every proposed check is implemented in the GUI.

This article is educational and does not recommend securities or trades, or guarantee returns. Historical research in the public course does not fully establish that only historically available information was used. Read the disclaimer.

Explore the j-quants learning path

• J-Quants and Point-in-Time Research
• Factor Analysis with J-Quants Data: Inputs and Evaluation
• J-Quants Listed Issues and Market Segments