Exceptions, differences between methods, and marketing

In effect, differences in methods mostly act upon the fluctuating balance of the most recent cycle (and are almost the same for balances carried over from cycle to cycle. Banks and consumers are aware of transaction costs, and banks actually receive income in the form of per-transaction payments from the merchants, besides gaining a new loan, which is more business for the bank. Therefore, the interest charged in the most recent cycle interrelates with other incomes and benefits to the cardholder and bank, such as transaction cost, transaction fees to the bank, marketing costs for gaining each new loan (which is like a sale for the bank) and marketing costs for overall cardholder perception, which can increase market share. Therefore, the rate charged on the most recent cycle is largely a matter of marketing preference based upon cardholder perceptions, rather than a matter of maximizing the rate.

Bank fee arbitrage and its limits

In general, differences between methods represent a degree of precision over charging the expected interest rate. Precision is important because any detectable difference from the expected rate can theoretically be taken advantage of (through arbitrage) by cardholders (who have control over when to charge and when to pay), to the possible loss of profitability of the bank. However, in effect, the differences between methods are trivial except in terms of cardholder perceptions and marketing, because of transaction costs, transaction income, cash advance fees, and credit limits. While cardholders can certainly affect their overall costs by managing their daily balances (for example, by buying or paying early or late in the month depending upon the calculation method), their opportunities for scaling this arbitrage to make large amounts of money are very limited. For example, in order to charge the maximum on the card, to take maximum advantage of any aribtragable difference in calculation methods, cardholders must actually buy something of that value at the right time, and doing so only to take advantage of a small mathematical discrepancy from the expected rate could be very inconvenient. That adds a cost to each transaction that obscures any benefit that can be gained. Credit limits limit how much can be charged, and thus how much advantage can be taken (trivial amounts), and cash advance fees are charged by banks partially to limit the amount of free movement that can be accomplished. (With no fee cardholders could create any daily balances advantageous to them through a series of cash advances and payments).

Cash rate

Most banks charge a separate, higher interest rate, and a cash advance fee (ranging from 1 to 5% of the amount of cash taken) on cash or cash-like transactions (called "quasi-cash" by many banks). These transactions are usually the ones for which the bank receives no transaction fee from the payee, such as cash from a bank or ATM, casino chips, and some payments to the government (and any transaction that looks in the bank's discretion like a cash swap, such as a payment on multiple invoices). In effect, the interest rate charged on purchases is subsidized by other profits to the bank.

Default rate

Many banks since 2000 have a contractual default rate (in the U.S., 2005, ranging from 10% to 36%), which is typically much higher than the regular APR. The rate takes effect automatically if any of the listed conditions occur, which can include the following: one or two late payments, any amount overdue beyond the due date or one more cycle, any returned payment (such as an NSF check), any charging over the credit limit (sometimes including the bank's own fees), and – in some cases – any reduction of credit rating or default with another lender, at the discretion of the bank. In effect, the cardholder is agreeing to pay the default rate on the balance owed unless all the listed events can be guaranteed not to happen. A single late payment, or even a non-reconciled mistake on any account, could result in charges of hundreds or thousands of dollars over the life of the loan. These high effective fees create a great incentive for cardholders to keep track of all their credit card and checking account balances (from which credit card payments are made) and for keeping wide margins (extra money or money available). However, the current lack of provable "account balance ownership" in most credit card and checking account designs (studied between 1990 and 2005) make these kinds of "penalty fees" a complex problem, indeed.

Variable rate

Many credit card issuers give a rate that is based upon an economic indicator published by a respected journal. For example, most banks in the U.S. offer credit cards based upon the lowest U.S. Prime Rate as published in the Wall Street Journal on the previous business day to the start of the calendar month. For example, a rate given as 9.99% plus the prime rate will be 16.99% when the prime rate is 7.00% (such as the end of 2005). These rates usually also have contractual minimums and maximums to protect the consumer (or the bank, as it may be) from wild fluctuations of the prime rate. While these accounts are harder to budget for, they can theoretically be a little less expensive since the bank does not have to accept the risk of fluctuation of the market (since the prime rate follows inflation rates, which affect the profitability of loans). A fixed rate can be better for consumers who have fixed incomes or need control over their payments budgets.

Grace period

Many banks provide an exception to their normal method of calculating interest, in which no interest is charged on an ending statement balance that is paid by the due date. Banks have various rules. In some cases the account must be paid off for two months in a row to obtain the discount. If the required amount is not paid, then the normal interest rate calculation method is still used. This allows cardholders to use credit cards for the convenience of the payment method (to have one invoice payable with one check per month rather than many separate cash or check transactions), which allows them to keep money invested at a return until it must be moved to pay the balance, and allows them to keep the float on the money borrowed during each month. The bank, in effect, is marketing the convenience of the payment method (to receive fees and possible new lending income, when the cardholder does not pay), as well as the loans themselves.

Promotional interest rate

Many banks offer very low interest, often 0%, for a certain number of statement cycles, on certain sub-balances ranging from the entire balance to purchases or balance transfers (used to pay off other accounts), or for buying certain merchandise in stores owned or contracted with by the lender. The cardholder gets lower interest, the payee gets more sales, and the bank gets a chance to increase income by having more money lent out, and possibly an extra marketing transaction payment from the payee or sales side of the business for helping to make the sale (in some cases as much as the entire interest payment, charged to the payee instead of the cardholder).
These offers are often complex, requiring the cardholder to work to understand the terms of the offer, and possibly to pay off the sub-balance by a certain date or have interest charged retro-actively, or to pay a certain amount per month over the minimum due (an "interest free" minimum payment) in order to pay down the sub-balance. Methods for communicating the sub-balances and rules on statements vary widely and do not usually conform to any standard. For example, sub-balances are not always reconcilable with the bank (due to lack of debit and credit statements on those balances), and even the term "cycle" (for number of cycles) is not often defined in writing by the bank. Banks also allocate payments automatically to sub-balances in various, often obscure ways. For example, they may contractually pay off promotional balances before higher-interest balances (causing the higher interest to be charged until the account is paid off in full.) These methods, besides possibly saving the cardholder money over the expected interest rate, serve to obscure the actual rate charged by the bank. For example, consumers may think they are paying zero percent, when the actual calculated amount on their daily balances is much more.

Rewards programs

This is a popular name (2005) for offers from card issuers (started by Discover Card in 1985) to share transactions fees with the cardholder through various games and bonus programs. Cardholders typically receive one "point", "mile" or actual penny (1% of the transaction) for each dollar spent on the card, and more points for buying from certain types of merchants or cooperating merchants, and then can pay down the loan, or trade points for airline flights, catalog merchandise, lower interest rates, gift cards, or cash. The points can also be exchanged, sometimes, between cooperating programs of different banks, making them more and more currency-like. These programs represent such a large value that they are not-completely-jokingly considered a set of currencies. These combined "currencies" have accumulated to the point that they hold more value worldwide than U.S. (paper) dollars, and are the subject of company liquidation disputes and divorce settlements (Economist, 2005). They are criticized for being highly inflationary, and subject to the whims of the card issuers (raising the prices after the points are earned). Many cardholders use a card for the points, but later forget or decline to use the points, anyway. While opening new avenues for marketing and competition, rewards programs are criticized in terms of being able to compare interest rates by making it impossible for consumers to compare one competitive interest rate offer to another through any standard means such as under the U.S. Truth in Lending Act, because of the extra value offered by the bonus program, along with other terms, costs, and benefits created by other marketing gimmicks such as the ones cited in this article.