Is there a law or regulation that governs the maximum allowable interest amount that can be charged on credit cards or in agreements where credit is extended?
The word you're looking for is usury - the crime of lending money at rates above an amount set by law. In Canada section 347 of the Canadian Criminal Code makes it illegal to charge more than 60% annually.  Since most Canadian credit card annual interest fee is below this they are within that legal limit.  However this is limited only to the rate and not necessarily a cap on the absolute interest charges. In the U.S., each state has its own local usury law. This website has a separate page for each state summarizing the local usury law and provides a reference to the local statute. The rules aren't simple: some set absolute limits, some appear to be pegged to something like the Prime Rate, some states don't have a general usury limit, the rules don't apply to certain loans because of the type of loan or lender, etc. There are US Federal laws dealing with usury, primarily in the context of racketeering -- the RICO Act lets the Feds go after racketeers that violate local usury laws beyond certain parameters. "In the US, usury is complicated and depends on the type of account, the bank charter and the where the bank makes credit decisions. Most major US credit cards are issued by entities in Utah, South Dakota and Delaware. None of these states have usury limits. Many states have usury limits. In New York, for example a loan may not exceed 16% interest, if the institution is supervised by the State.  Credit card issuers are usually chartered as ""National Associations"" (ie Federally chartered banks regulated by the Comptroller of the Currency). There is no Federal usury statute, and Federally chartered banks are allowed to ""export"" many of the regulations of the state where credit decisions are made. Small states like South Dakota basically design their banking regulations to meet the needs of the banks, which are major employers." What are those maximums, and do all countries have them? Usury, lending money for any interest at all, used to be anti-biblical: it wasn't a Christian thing to do, and so in Christian countries it was Jews who did it (Jews who were money-lenders). Asking for interest on loans is still anti-Koranic: so Islamic banks don't lend money for interest. Instead of your getting a mortgage from the bank to buy a house, the bank will buy the house, which you then buy from bank on a rent-to-own basis. Further details: In the EU, you might be looking for Directive 2000/35/EC (Late Payment Directive). There was a statutory rate, 7% above the European Central Bank main rate. However, this Directive was recently repealed by Directive 2011/7/EU, which sets the statutory rate at ECB + 8%. (Under EU regulations, Directives must be turned into laws by national governments, which often takes several months. So in some EU countries the local laws may still reflect the old Directive. Also, the UK doesn't participate in the Euro, and doesn't follow the ECB rate)
"I'm not sure if the rules in Canada and the US are the same. I'm as amazed as you are by the amounts of debts people have, but I can see how this credit can be extended. Generally, with good credit history and above average pay - it is not unheard of to get about $100K credit limit with a bunch of credit cards. What you do with that after that depends on your own ability to manage your finances and discipline. Good credit history is defined by paying your credit cards on time with at least minimum payment amount (which is way lower than the actual statement amount). Above average pay is $60K+. So you can easily have tons of debt, yet be considered ""low risk"" with good credit history. And that's the most lucrative market for the credit card issuers - people who do not default, but also have debt and pay interest." Just to put in one more possibility: my credit card can have a positive balance, in which case I earn interest.  If more money is due, it will automatically take that from the connected checking account. If that goes into negative, of course I have to pay interest.  I chose (argued with the bank in order to get) only a small credit allowance. However, I'll be able to access credit allowance + positive balance. That allows me within a day or so to make larger amounts accessible, while the possible immediate damage by credit card fraud is limited at other times.  Actually, the credit card pays more interest than the checkign account. Nevertheless, I don't keep high balance there because the risk of fraud is much higher for the credit card. "Charging interest by non financial institutions is allowable. There is only one definition of illegal or criminal interest and this is regarding loan sharks.  Section 347 of the Canadian Criminal Code makes it illegal to charge more than 60% annually.   The biggest debate was whether or not ""pay day"" loan companies were breaking the law.  The recent bill C-26 amends this section to exempt ""pay day"" loans from this definition." Yes. it is possible, I have seen many times banks permitting overdrawing and later charging a high courtesy fees. Of course in many countries this is not permitted. In one of my account, I am running negative balance as the bank has charged its commission which is not due. a typical debit card is subject to several limits: I'm in the US, and I can't speak for all credit cards, but I have done this in the past. I've paid extra on my credit card, and had a positive balance on my credit card account. The purchases made after paying extra were applied to the balance, and if there was money left over on the statement closing date, I didn't owe anything that month.  Of course, I didn't incur any interest charges, but I never pay interest anyway, as I always pay my statement in full each month and never take a cash advance on my credit card.  You could call your credit card company and ask them what will happen, or if you are feeling adventurous, you could just send them some extra money and see what happens. Most likely, they will just apply it to your account and give you a positive balance. I've got a card that I've had for about 25 years now.  The only time they charged me interest I showed it was their goof (the automatic payment failed because of their mistake) and they haven't cancelled it.  No annual fee, a bit of cash back. The only cards I've ever had an issuer close are ones I didn't use. A credit card is essentially a contract where they will loan you money in an on demand basis.  It is not a contract for you to loan them money. The money that you have overpaid is generally treated as if it is a payment for a charge that you have made that has not been processed yet.  The bank can not treat that money as a deposit and thus leverage it make money them selves. You can open an account and get a debit card.  This would allow you to accrue interest for your deposit while using your money.  But if you find one willing to pay you 25% interest please share with the rest of us :) "The interest rate is determined by your 401(k) provider and your plan document.  Of course you may be able to influence this, depending on your relationship with the provider.  I'm very certain that prime+1% is not the only rate that is possible.  However, your provider is constrained by IRC 4975(d), which states that the loan must be made ""at a reasonable rate of interest.""   The definition of ""reasonable rate of interest"" would probably need to go to court and I do not know if it has.  The IRS probably has internal guidelines that determine who gets thrown to the dogs but they would not make those public because it takes away their discretion.  Because of the threat of getting pounded by the IRS, I think you will have a hard time getting a provider to allow super high or super low interest rate loans. Note: I am not a lawyer." "I'm not sure that OP was asking if he/she personally should have more available credit, so I will answer the other interpretation: should that particular card have a higher limit? The answer is ""no.""  The range varies vastly by issuer.  Starting limits vary widely from issuer to issuer even with identical credit histories.  Some issuers never automatically increase the limit, some periodically conduct account reviews to determine if an increase is warranted.  Some like to see higher spending habits each month.  Personally, my cards range from $500 to $25000, and the high and low extremes are the same age. You can search for tips on how often to request increases for your particular card, or what kind of spending habits the issuer prefers.  An important note: You do not need to carry a balance to make the issuer happy.  You never need to pay a cent in credit card interest." "This is most likely protecting Square's relationship with Visa/Mastercard/AMEX/etc. Credit card companies typically charge their customers a much higher interest rate with no grace period on cash advances (withdrawals made from an ATM using a credit card). If you use Square to generate something that looks like a ""merchandise transaction"" but instead just hand over a wad of banknotes, you're forcing the credit card company to apply their cheaper ""purchases"" interest rate on the transaction, plus award any applicable cashback offers†, etc. Square would absolutely profit off of this, but since it would result in less revenue for the partner credit card companies, that would quickly sour the relationship and could even result in them terminating their agreements with Square altogether. † This is the kind of activity they are trying to prevent:  1. Bill yourself $5,000 for ""merchandise"", but instead give yourself cash.  2. Earn 1.5% cashback ($75).  3. Use $4,925 of the cash and a $75 statement credit to pay your credit card statement.  4. Pocket the difference.  5. Repeat. Note, the fees involved probably negate any potential gain shown in this example, but I'm sure with enough creative thinking someone would figure out a way to game the system if it wasn't expressly forbidden in the terms of service" I did just what you suggest. The card company honored the charge, they told me the temporary number was solely for the purpose of assigning a number to one vendor/business. So even though I set a low limit, the number was still active and the card company paid the request. Small price to pay, but it didn't go as I wished.    For this purpose, I've used Visa/Mastercard gift cards. They are often on sale for face value and no additional fees. Contrary to what many people think, credit card companies pass nearly all fraud costs via purchased goods onto the merchant who sells them. As a result, they stand a very high chance of getting the money from a fraudulent purchase of a specific purchased item back, as they just chargeback the merchant who has to stomach the cost. This is not the case for cash transactions obviously, where as soon as the money leaves the ATM fraudulently it is as good as gone. As a result, the risk profile of the two types of transaction is wildly different, and the credit limits of each reflect this. The minimum amount is set by the merchant services provider based on the kind of business, its location and the history. It mostly has nothing to do with you personally. However, the minimum amount differs based on the kind of credit cards being used. For example, foreign credit cards will require signatures on much lower amounts than domestic.  In my local Safeway (NoCal analog of Ralph's) the limit for domestic credit cards is set at $50. If your credit limit is $5000, you might think that its a 1% of your limit. But if your limit is $50000 or $500 - it will still be $50. You cannot deduce anything about a specific person's credit situation based on whether or not they are required to sign the receipt. It has no affect on the decision. "There are some loan types where your minimum payment may be less than the interest due in the current period; this is not true of credit cards in the US.  Separately, if you have a minimum payment amount due of less than the interest due in the period, the net interest amount would just become principal anyway so differentiating it isn't meaningful. With credit cards in the US, the general minimum calculation is 1% of the principal outstanding plus all interest accrued in the period plus any fees.  Any overpayment is applied to the principal outstanding, because this is a revolving line of credit and unpaid interest or fees appear as a charge just like your coffee and also begin to accrue interest.  The issue arises if you have multiple interest rates.  Maybe you did a balance transfer at a discounted interest rate; does that balance get credited before the balance carried at the standard rate?  You'll have to call your lender.  While there is a regulation in place requiring payment to credit the highest rate balance first the banks still have latitude on how the payment is literally applied; explained below.   When there IS an amortization schedule, the issue is not ""principal or interest"" the issue is principle, or the next payment on the amortization schedule.  If the monthly payment on your car loan is $200, but you send $250, the bank will use the additional $50 to credit the next payment due.  When you get your statement next month (it's usually monthly) it will indicate an amount due of $150.  When you've prepaid more than an entire payment, the next payment is just farther in to the future.  You need to talk to your lender about ""unscheduled"" principal payments because the process will vary by lender and by specific loan. Call your lender.  You are a customer, you have a contract, they will explain this stuff to you.  There is no harm that can possibly come from learning the nuances of your agreement with them. Regarding the nuance to the payment regulation: A federal credit card reform law enacted in May 2009 requires that credit card companies must apply your entire payment, minus the required minimum payment amount, to the highest interest rate balance on your card.  Some credit card issuers are aggressive here and apply the non-interest portion of the minimum payment to the lowest interest rate first.  You'll need to call your bank and ask them."