Aims: Online platforms enable real-time trading activities that are similar to those of gambling. This study aimed to investigate the associations of traditional investing, real-time stock trading, and cryptocurrency trading with excessive behavior and mental wellbeing.Design: Cross-sectional population survey.Setting: Population-based survey in Finland.Participants: Finnish people aged 18–75 years (N = 1530, 50.33% male).Measurements: Survey asked about monthly regular investing, real-time stock-trading platform use, and cryptocurrency trading. The study had measures for excessive behavior: gambling (Problem Gambling Severity Index, PGSI), gaming (Internet Gaming Disorder Test, IGDT), internet use (Compulsive Internet Use Scale, CIUS), and alcohol use (AUDIT-C). Psychological distress (Mental Health Inventory, MHI-5), perceived stress (Perceived Stress Scale, PSS), COVID-19 anxiety, and perceived loneliness were also measured. Background factors included socio-demographic variables, instant loan taking, and involvement in social media identity bubbles (Identity Bubble Reinforcement Scale, IBRS-9)Findings: Within the sample, 22.18% were categorized into monthly regular investors only, 3.00% were investors using real-time stock-trading platforms, and 3.48% were crypto-market traders. Real-time stock-trading platform use and cryptocurrency trading were associated with younger age and male gender. Real-time platform users were more involved in social media identity bubbles than non-investors. Cryptomarket traders were more likely to have an immigrant background and have taken instant loans. Both real-time stock-trading platform use and cryptomarket trading were associated with excessive forms of gambling, gaming, and internet use. Cryptomarket traders had more issues with mental wellbeing, manifested in higher psychological distress, perceived stress, and loneliness.Conclusions: Regular investing is not a risk factor for excessive behavior. However, rapid online trading platforms and applications were significantly more commonly used by participants reporting excessive behavior and mental health issues. The strong association between cryptomarket trading and excessive behavior in particular underlines the need for harm prevention policies in this area of trading practices.Funding: The study was funded by the Finnish Foundation for Alcohol Studies (Gambling in the Digital Age Project, 2021, PI: A. Oksanen). Ilkka Vuorinen was supported by grant from the Jenny and Antti Wihuri Foundation.Declaration of Interest: None of the authors have a conflict of interest to declare.Ethical Approval: The study was approved by the Academic Ethics Committee of Tampere region inFinland in March 2021.