Patent ID: 8374936

Claim:
A computer-implemented method comprising: retrieving a plurality of computer-executable instructions from computer-readable storage; and executing the computer-executable instructions on at least one computer processor, thereby causing computer hardware to perform operations comprising: associating each of a plurality of financial accounts with a financial account card, each account having a payment plan and integrating both credit transactions and savings transactions into a single account balance with different effective interest rates; defining account payment plans that each have a fixed amortization rate, a variable fixed or adjustable effective interest rate, a payment cycle, an account unit value, an adjustment index of value and an indicator of whether or not the effective interest rate is proportionally applied in a first cycle between a transaction date and a deadline of the cycle; and initiating an entry of an effective value as a credit transaction in a first cardholder account and as a savings transaction in a second cardholder account, wherein the first cardholder account and the second cardholder account share a same payment plan and are issued by a same financial institution, wherein the entry is facilitated by a computer, wherein a credit transaction creates or increases a debt balance, changes a savings balance to a debt balance, or diminishes or liquidates a savings balance, wherein a savings transaction creates or increases a savings balance, changes a debt balance to a savings balance, or diminishes or liquidates a debt balance, and wherein the first cardholder account corresponds to a buyer and the second cardholder account corresponds to a seller of at least one of a good, a service, money, or a security that has an effective value, wherein the balances of the accounts are previously updated to values financially equivalent, each time a current effective interest rate changes, considering the current effective interest rate, the last effective interest rate and other parameters of the payment plan.