<![CDATA[Purpose: This study examines the effect of production costs and sales volume on the net profit of CV Sini Suka Berastagi. Research Method: A quantitative approach was used, drawing on 36 monthly observations from January 2023 to December 2025 obtained from the company’s internal records. Sampling was conducted using the saturation sampling method. The data were analyzed using multiple linear regression with IBM SPSS Statistics 29. Given the sequential nature of the observations, temporal patterns and stationarity were examined using monthly graphs and the Augmented Dickey–Fuller (ADF) test via EViews version 14, while residual dependence was assessed using the Durbin–Watson and Ljung–Box tests. Results and Discussion: The overall regression model is statistically significant, indicating that production costs and sales volume jointly explain variation in net profit. However, this result does not indicate an interaction effect between the predictors, and the individual contributions of each variable remain distinct. Implications: The findings suggest that sales volume had a stronger statistical contribution than production costs in explaining monthly net profit variation. Managerial implications should be considered within the context of the observed firm and period. Originality: This study provides firm-level empirical evidence from a carrot-washing and distribution business in Berastagi, highlighting the greater role of sales volume than of production costs in determining net profit.]]>
