Abstract this study aims to examine the effect of purchases from related parties, sales to related parties, funding sources and supply turnover to operating profits, both jointly and individually. the four independent variables will be tested for their influence on one non-independent variable, namely operating profit. this research includes all population elements that have met the criteria, as many as 65 companies become observations. observations from 2009-2017 were on automotive sector companies and components. the analytical method used is multiple linear regression. the results of this study found that purchases from related parties and inventory turnover have a positive effect on operating income. whereas sales to related parties and funding sources negatively affect operating income. keywords: operating profit, purchases from related parties, sales to related parties, sources of funding, inventory turnover