This paper investigates how CEOs in public Swedish mid-cap corporations time their transactions in their own company’s stock in a short-term perspective. To investigate this, an event study methodology is employed on cumulative returns surrounding these insiders’ transactions, both absolute and relative to the market. We find that these insiders, on average, purchase stock subsequent to a period of decline in both total and abnormal cumulative returns and sell stock following a period of positive total and abnormal returns. This is in line with our hypotheses. We also find that total and abnormal cumulative returns tend to turn and increase for a short period following a purchase transaction, while for a sale transaction, the trend does not turn but continues upward, implying that purchases may be timed more rigorously in the short run than sales. This paper discusses these observations in connection to earlier findings and motivates further research on the subject of insider transaction timing.

Background: In financial markets, decisions to buy or sell securities are highly influenced by the aim of making a profit and avoiding losses. The signals that insider transactions send to external investors can significantly impact those decisions. The signals can differ depending on the type of transaction, within which sector, and the company's size. Purpose: The purpose of this thesis is to investigate whether insider transactions employ a more potent influence when buying or selling stocks. A partial purpose is distinguishing between small- and mid-cap stocks and between the technology and industrial sectors on the Nasdaq Stockholm Stock Exchange. Methodology: A quantitative approach was utilised with the event Study model. Hypotheses were constructed, and statistical tests in STATA were conducted to determine if the results were significant. The insider trading that was analysed took place between 2018-2023. Thirty-one companies are in the industrial sector, and twenty-eight are in the technology sector, with 3601 insider transactions employed. Conclusion: The results showed the existence of signalling effects and the possibility of achieving abnormal returns, especially if shorting when insiders are selling, particularly technology stocks, with the most prominent returns from mid-cap firms. However, the results contradict most previous research proposing that purchase transactions yield higher abnormal returns and have a more substantial signalling effect.