BTL stands for "Below The Line" marketing. It refers to marketing activities that are targeted at specific, targeted groups of consumers and are not part of a company's mass-market advertising. BTL marketing is often used to complement a company's Above The Line (ATL) marketing efforts, which are more broad-based and aim to reach a mass audience.
BTL marketing activities can include tactics such as:
direct mail
in-store promotions
events
product demonstrations, etc.
These activities are designed to create a direct, personal connection with consumers and generate a higher level of engagement and response compared to more traditional, mass-market advertising methods.