The soybeans complex represents a fundamental role in the brazilian agribusiness. However, at the time of soybeans marketing, producers face a dilemma: "when", "how much" and "how" to sell their production, due to the uncertainties of this activity under risk conditions. By this way, using a mathematical model of quadratic programming, this work has searched for the best portfolio, trying to increase their incomes with some level of risk or to decrease risks at some income level. The most efficient plan is related to producers with medium risk aversion (α = 0,3). This optimum marketing plan shows that soybean producers of Paraná State could store production at the harvest time in order to sell later following, for instance, this schedule: 21,9% in September; 25,1% in October; 19,9% in November and 23,9% in December, which means that 90,8% of all sales concentrated on the last four months of the year.
Soybeans; risk; portfolio; quadratic programming
