Business process “receivables management” is a key position both in the system of financial management of the telecommunications company and its operating activities. The need for optimization of the business process is determined by its influence on financial performance. The paper considers the approach to optimize the business process within the framework of the Six Sigma methodology. To define accounts receivable probability, logit regression mathematical model has been proposed. The paper also considers the issue of the selection of terms for service payment in order to approximate the level of accounts receivable to the optimal value.