Before Treating Insider Buying or Selling as a Signal, Check the Transaction Type
Distinguish trade dates from filing dates, plans from execution, and market purchases from gifts in executive and major shareholder transactions. Interpret the economics behind ownership changes.
An increase in an insider's share count alone does not establish confidence in the company's prospects. First check whether the shares were bought in the market with the insider's own money or acquired through compensation, inheritance, a gift, or conversion.
Record trade dates, disclosure dates, and plan dates separately
Ownership reports confirm actual changes, while advance trading plans describe intended future transactions. In 2024, the Financial Services Commission introduced advance disclosure for certain large insider transactions. Check the latest rules and the relevant report for specific coverage and exemptions. Do not summarize an announced plan as a completed trade. Assuming the trade occurred on the disclosure date also ignores the reporting lag. Use the transaction date to compare the trade with other information publicly available at the time.
Connect the reason for the share increase to its monetary amount
For a cash market purchase, quantity and price allow calculation of the amount actually invested. For a stock option exercise, examine the exercise price, shares retained after acquisition, and subsequent sales. A share count increase from a bonus issue or stock split may simply change the units representing the same economic interest. Gifts within a family or transfers between affiliates differ from market purchases reflecting an individual's outlook. When combining multiple reports dated the same day, avoid double-counting transfers among related parties as new purchases.
Build comparable context rather than guessing motives
Sales can have many motives, including taxes, living expenses, diversification, or monetizing compensation, so a disclosure alone cannot establish the seller's intentions. As supplementary context, look at the transaction's size relative to prior holdings, whether it recurs, and whether several insiders act similarly, rather than focusing on a single small trade. Even then, it does not replace business results. A disclosed transaction and the legal assessment of the use of material nonpublic information are also separate matters. Do not suggest that disclosure resolves every legal issue. When only the ownership percentage changes, also check whether the share count held is unchanged. A company share issue can increase the denominator and reduce an insider's percentage without the insider selling a single share. Avoid incorrectly classifying this as an insider sale disclosure.
Worked example
Hypothetical example: An executive buys 5,000 shares in the market at KRW 20,000 each, investing KRW 100 million before fees. If the previous holding was 50,000 shares, the share count increases by 10%. If another executive's 5,000-share increase came from a bonus issue allocation, combining the two and stating that management invested KRW 200 million would be incorrect. Use a separate row for each transaction type and total only confirmed cash investments.
What to check
- Distinguish trading plans from reports of actual ownership changes.
- Record transaction and filing dates separately.
- Classify market purchases, exercises, gifts, and changes in share units.
- Calculate the change relative to prior holdings and the confirmed amount invested.
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.