Background and Aims: There is growing evidence regarding the overlap between trading behaviors and gambling. However, problematic trading behaviors are often assessed using gambling-related instruments, which may not fully capture the nuances of trading. The present study developed and evaluated the psychometric properties of the Trading Disorder Scale (TDS), grounded in in the research criteria proposed by Guglielmo et al. (2016), based on DSM-5 criteria for gambling disorder and internet gaming disorder. Methods: A cross-sectional survey was administered to 403 Spanish amateur traders. The TDS was tested for reliability, validity, and factorial structure. Latent class analysis (LCA) was used to identify patterns of disordered trading. Results: EFA and CFA supported a one-factor solution for the TDS, which showed strong internal consistency (ƒÖu-cat 5 0.938, KR-20 5 0.877). The scale showed good concurrent validity with PGSI (r 5 0.559) and good convergent validity with trading-related variables. LCA identified three classes: non-disordered trading (72.2%), at-risk trading (17.6%), and disordered trading (10.2%). Individuals in the disordered trading group scored higher on TDS, traded more frequently, monitored markets more intensively, and exhibited higher rates of problem gambling (PGSI.5), impulsivity, and substance use. Guglielmofs cut-off point (.5 criteria) effectively differentiated individuals with disordered trading behaviors from those at-risk and those without disordered trading. Conclusions: The TDS is a reliable and valid instrument for assessing disordered trading among amateur investors. Further research is needed to explore the scalefs predictive validity.  Kulcsszavak: behavioral addiction, gambling, trading addiction, cryptocurrency, stock market trading, psychometric evaluation