Smart use of liquidity is a priority for the treasurers in charge of the payments’ operations and it is a requirement for the authorities responsible for liquidity provision. Technological innovation and the growing sophistications of financial services has created new challenges to existing arrangements in order to have wider public access, more efficient processing and quicker settlements of payments. These newcomers in the payment service industry, also referred as Fintech startups, have created new challenges to policy maker and arguably their pressure will allow retail payment systems to unlock its potential - the improvements in standards of living to unbanked and underbanked consumers. Authorities need to answer the questions: a) who should be the ultimate payment service provider? b) are current arrangements of settlement mechanisms the most appropriate in terms of speed/liquidity consumption ratio? c) how industrial arrangements toward digitalization of payment activates could accelerate changes in customers/participants payment habits? The contribution of the present study is in line with the second questions, focusing on the design of settlement mechanisms able to process in real time large and low payments simultaneously. The paper aims to identify and explain the funding patterns in payments from size and sender perspectives. We expect that the use of external funds towards incoming payments will depend on two factors: i) who origins the payment, third parties (clients) or participants, and ii) the size of the payment, low vs high value. We classify the size into six different categories combining dynamic clustering approach and expert knowledge. For the study we use transactional data of the Mexican Real Time Payment System, SPEI, for the year 2014.