Ed Sunarpo
Publications
EducationalAcres Research2024

The December & January Effect in Indonesia

Do seasonal market patterns actually exist in Indonesia, or are the December and January effects simply investment myths?

Published on InstagramOpen

Findings

  1. 01December has historically been the strongest month for the JCI, averaging a 3.67% return with a 92% probability of a gain since 2000.
  2. 02While January is often associated with stronger equity returns globally, the JCI has averaged just 0.9% in January since 2000, showing no meaningful advantage over other months.
  3. 03The January Effect has largely disappeared from both the S&P 500 and JCI, suggesting that the historical anomaly is no longer a reliable seasonal pattern.
  4. 04Seasonal rallies can become self-fulfilling as investors anticipate higher prices, but market anomalies should be treated cautiously rather than used as a substitute for fundamental research.