In some large transactions in the Chilean market, in which the existence of a conflict of interest situation for the controller of a publicly traded company is apparent, it has been discussed whether or not that transaction is a related party transaction. The answer has not been unanimous, neither from the market, nor from academia, nor between the financial authority and the justice, which may be attributed to conceptual issues. This paper aims to contribute to legal certainty for this type of transactions, by specifying the concept of related party transactions, the scope of its regulation and by the analysis of construction criteria used in difficult cases that have taken place in Chile.