Psychology of reciprocity applied to business and investments. The human being has a natural impulse to return favors. This principle of psychology is powerful in negotiations: offering value before asking for something increases the chances of closure. In business, free samples or quality content are examples of applied reciprocity. In the field of investments, consultants and managers who share valuable information create bonds of trust, increasing the likelihood of new contributions. Reciprocity, used as a conscious strategy, transforms commercial relationships into lasting partnerships.