Kan insiderköp leda till högre avkastning än index på kort sikt? : En kvantitativ studie om insiderhandel på Svenska kapitalmarknaden

Sammanfattning

Purpose: The purpose of the study is to examine whether insiders can generate asignificant excess return relative to a benchmark index in the short term during theperiod 2024–2025. Furthermore the study aims to evaluate whether investors find valuein following insider trading activity. Methodology: The study was conducted using a quantitative research approach in theform of an event study based on secondary data collected from the Swedish FinancialSupervisory Authority’s insider register and stock price data from Nasdaq OMXStockholm. The event study includes 469 transactions within the specified limitationsduring the period 2024–2025. To analyze whether insider purchases generated excessreturns, the stocks’ performance was compared to the benchmark index (OMX) over aperiod of 30 trading days. The results were statistically analyzed using t-tests in SPSS toexamine whether the abnormal returns were significant. Results: T-tests for the study showed a positive and statistically significant excessreturn relative to the index of 1.57% for the entire period. This result was primarilydriven by the outcomes in 2024, which amounted to 2.45%. In 2025, excess returnsdeclined to 0.72%, and the result for that year was not statistically significant, as itexceeded the significance threshold of p < 0.05. The study conducted t-tests on 469insider purchase transactions during the years 2024–2025. Conclusions: The results of the study indicate that it is possible to generate positiveexcess returns relative to the index in the short term by following insider tradingactivity. The findings therefore suggest that insider purchases contain information thatis not immediately fully reflected in market pricing. However, external factors may alsocreate uncertainty in the market, which can negatively affect the strategy and thus nolonger guarantee that the risk taken by the investor will generate positive alpha in thelong run. Keywords: Information asymmetry, Insider, Trading volume, Actual average return,Insider trading, and Insider transaction.