The advancement of the digital world has been made. Access to knowledge from many platforms substantially benefits the community. In keeping with the effective method of working from home during the Covid-19 pandemic, information media is increasingly becoming a space and medium for making investment decisions, enabling the rise and development of investor financial behavior bias. The purpose of this research is to advance behavioral economics, specifically behavioral biases in capital market investment decisions using the echo chamber perspective as a social media representation. The data used is those of online capital market investors with social media or investor community groups. PLS-SEM is used to analyze data (Partial Least Square-Structrural Equation Modeling). Overconfidence, familiarity effect, and irrational exuberance all have a substantial effect on investment decisions in the Indonesian capital market, however gambler's fallacy, financial cognitive dissonance, and echo chamber have no significant effect.