Credit Cards

Watch a video that visualizes what really happens inside a credit card network when you make a purchase.

Every tap sets off a lightning-fast relay. When someone buys coffee with their Visa, a tiny "runner" races between the coffee shop's bank, Visa's network, and their bank—all in under a second. The catch? No money has actually moved yet. Here's what really happens behind that instant "Approved."

Why there are microchips in credit cards

Credit cards have evolved significantly since their invention in 1950, but security lagged in the US for years. Despite handling only a quarter of global transactions, the US once accounted for half of all credit card fraud. The 2013 Target data breach helped push the adoption of chip cards, reducing fraud but shifting risks to online scams.

Credit card issuers determine your credit limit using your payment history, income, and more

Some credit card issuers also take your other payment obligations into account when determining your credit limit, such as the cost of your rent or alimony.

Credit cards were the fourth-highest source of US consumer debt as of 2024

US consumer debt nationwide totaled $17.9T as of 2024 Q3. Mortgage debt ranked as number one, with student loan debt coming in at number two.

See an original Diner’s Club charge card

Before credit cards, there were charge cards from companies like Diner’s Club. While credit cards allow cardholders to carry a balance from month to month (potentially accruing interest), charge cards like Diner’s Club cards had to be paid off right away.

Charge cards are different from credit cards

Unlike credit cards, charge cards often don’t have a preset credit limit, but cardholders need to pay off the entire balance every month.

Why Americans are drowning in credit card debt

Americans owe more than $1T to credit card companies. And with rising interest rates that prevent cardholders from paying down debt (not to mention the rising cost of living), that number is likely to keep growing. A podcast episode explains how the US got here, and what policymakers and individuals can do about it.

Visa, the first credit card network, still dominates competitors with a roughly 52% market share by purchase volume.

Among the major credit card companies in the US, Mastercard had about 25% of the market share in 2025. American Express had roughly 20%, and Discover had the smallest market share of about 4%.

See the growth of US consumer debt

Americans reached an all-time high debt burden in 2024. Data compiled from The Kaplan Group shows the evolution of auto loans, mortgages, credit card debt, and student loans from 2003 to 2023, and finds that after a brief decline after 2008, the total debt burden grew rapidly.

Financial institutions check for lots of things before authorizing a purchase

Before authorizing a purchase, card issuers consider whether or not the cardholder has a high enough available credit limit to make the purchase, where the purchase is being made in order to reduce fraud, and more.