Using various embodiments, methods and systems for implementing secure transaction transfers are described. In one embodiment, a system performing the techniques described herein maintains a multi key index associated with a plurality of financial transactions using a self-balanced sorted tree data structure. Thereafter, the system reads/stores the self-balanced sorted tree data structure into memory and applies a filtering algorithm on the self-balanced sorted tree data structure to determine at least one qualifying financial transaction out of the plurality of financial transactions. The system selects the at least one qualifying financial transaction if it does not exceed a predetermined value. In one embodiment, the predetermined value is determined based on an available maximum utilization amount available to a user. Thereafter, the system transfers the selected at least one qualifying financial transaction to a secured credit card.