Ramadan Effect, one type of market anomaly, is a seasonal anomaly which shows a difference in average returns in the month of Ramadan compared to other months in one year. The phenomenon of increasing public consumption in the month of Ramadan is suspected to be a phenomenon that causes returns in Ramadan, especially in food and beverages companies different from the months outside of Ramadan. Ramadan in Indonesia has distinctive nature compared to Ramadan in other countries, namely the activity of giving each other food, so that product demand of food and beverages companies also increases. This study used the calculation of risk and returns portfolio to determine the level of risk and return portfolio of food and beverages companies during the month of Ramadan. Purposive sampling was chosen with the criteria of 3 companies that most actively moved their shares in food and beverages sector. Data analysis was explained using financial Mathematics. Based on the calculation, it was shown that PT. Indofood Sukses Makmur, Tbk (INDF) had-1.67% of return and stocks risk at 2.67%, PT. Ultrajaya Milk Industry and Trading Company, Tbk (ULTJ) had-0.19% return and 0.33% stocks risk, while PT. Siantar Top, Tbk (STTP) had 4.70% return and stocks risk at 8.31%. Calculating using portfolio calculation to minimize the risk was proven to be successful method. It showed that the individual stocks risk from the three companies could be reduced to 2.91% with positive return at 0.95%.