The US borrows money by selling Treasury bonds and bills to investors around the world

When the federal government spends more money than it collects in taxes, it borrows the difference by issuing Treasury securities—IOUs that promise to pay back the money with interest. These are sold to investors, banks, and other governments. The largest lenders to the US are not foreign countries but American investors: individuals, pension funds, and banks hold the majority of US debt. Foreign governments and central banks, particularly China and Japan, hold significant amounts, but they are not the primary lenders.

The US Treasury Department runs this borrowing operation. When the government needs cash, Treasury auctions off these securities to the highest bidders. Investors buy them because they are considered extremely safe—backed by the full faith and credit of the US government—and they pay interest. The interest rate depends on how long you lend the money and how much risk investors perceive at that moment.

Key Takeaways

  • The US borrows money by selling Treasury bonds, notes, and bills to investors worldwide, with Americans holding the majority of the debt.
  • The Treasury Department auctions these securities regularly, and investors buy them because they pay interest and are considered very safe.
  • Foreign governments like China and Japan hold significant US debt, but they are not the largest lenders overall.
  • The interest rate on Treasury securities changes based on demand and how long the money is borrowed for, ranging from a few weeks to 30 years.

Who actually owns US government debt

Domestic investors—Americans and American institutions—own roughly 70 percent of all US government debt. This includes individual savers who buy Treasury bonds through their banks or brokers, pension funds that invest retirement money, mutual funds, insurance companies, and the Federal Reserve itself. When you buy a Treasury bond, you are lending money to the US government.

Foreign investors and governments own the remaining 30 percent. China holds the largest foreign share, followed by Japan, the United Kingdom, and others. These countries buy US Treasury securities as a way to store wealth and earn a return. They are not forced to lend; they choose to because US debt is considered a safe investment. If a foreign government stopped buying US debt tomorrow, it would not cause an when ready crisis—the Treasury would straightforward auction the securities to other buyers, though possibly at a higher interest rate.

The three types of Treasury securities the government sells

The US Treasury sells three main types of borrowing instruments, each with a different repayment timeline. Treasury bills are short-term loans that mature in a few weeks to one year. Treasury notes mature in two to ten years. Treasury bonds are long-term loans that mature in 20 or 30 years. The longer you agree to lend money, the higher the interest rate you receive, because you are taking on more risk that inflation or other economic changes will reduce the value of your return.

The Treasury holds auctions regularly—bills are auctioned weekly, notes and bonds monthly or quarterly. At each auction, investors bid on how much interest they are willing to accept. If many investors want to buy, the interest rate can be lower. If few investors want to buy, the Treasury must offer a higher rate to attract lenders. This is how market demand directly affects how much it costs the government to borrow.

How the Federal Reserve fits into government borrowing

The Federal Reserve, which is the nation's central bank, can also lend money to the government or buy Treasury securities from the open market. When the Fed buys Treasuries, it is using money it creates electronically. This is different from regular investors, who must have actual money to lend. The Fed does this to influence interest rates and the money supply during economic crises or recessions.

During the 2008 financial crisis and the 2020 pandemic, the Fed bought large amounts of Treasury securities to keep interest rates low and inject money into the economy. This is sometimes called quantitative easing. The Fed currently holds a significant portion of US debt, though it is required by law to eventually sell these securities back into the market or let them mature. The Fed's actions are separate from regular Treasury borrowing, but they affect how much the government pays in interest overall.

Why interest rates on Treasury securities change

The interest rate the Treasury pays depends on two main factors: how long the loan lasts and how much risk investors perceive. A 30-year bond pays more interest than a 3-month bill because you are lending money for much longer and inflation could erode its value. If investors believe the government might struggle to repay—which is rare for the US but happens in other countries—they demand higher interest rates as compensation for that risk.

Economic conditions also matter. When the economy is strong and investors have many places to put their money, they may demand higher rates from the Treasury to make lending to the government competitive. When the economy weakens and investors seek safety, they buy more Treasuries even at lower rates. The Federal Reserve's interest rate decisions also influence Treasury rates, since investors compare the return on government bonds to other investments.

What happens if the US cannot borrow more money

Congress sets a legal limit on how much debt the US can carry, called the debt ceiling. When the government approaches this limit, Congress must vote to raise it or the Treasury cannot borrow more money. If Congress does not raise the ceiling and the Treasury runs out of cash, the government cannot pay all its bills—it would have to choose which obligations to meet, such as Social Security, military salaries, or interest on existing debt.

This has never happened in US history. Congress has always voted to raise the debt ceiling before a default occurs, though sometimes after intense political debate. If it did happen, it would damage the US credit rating, make future borrowing more expensive, and likely cause economic disruption. Investors would lose confidence that the US would repay its debts, and interest rates would spike.

How much interest does the US pay on its debt

The total amount the US pays in interest each year depends on how much debt exists and what interest rates are. When interest rates are low, the government pays less. When rates are high, the government pays more. In recent years, as the Federal Reserve raised interest rates to fight inflation, the cost of borrowing increased. The government now spends tens of billions of dollars per month just on interest payments to debt holders.

This interest payment is a real government expense, like any other. It comes from tax revenue. As debt grows and interest rates stay high, interest payments take up a larger share of the federal budget, leaving less money for other programs. This is why some economists worry about the long-term sustainability of current borrowing levels, though others argue the US can manage higher debt because it borrows in its own currency and has a large, productive economy.

Frequently Asked Questions

Can the US run out of money to borrow?

The US can always find lenders because Treasury securities are considered very safe and pay interest. However, Congress has set a legal debt ceiling that limits how much the government can borrow. If Congress does not raise this ceiling, the Treasury cannot issue new securities, even though investors would be willing to buy them. This is a political constraint, not an economic one.

Why do foreign countries lend money to the US?

Foreign governments and investors buy US Treasury securities because they are safe, pay interest, and can be sold quickly if needed. Countries like China and Japan also hold US debt as part of their foreign exchange reserves—money they keep on hand for international transactions. Lending to the US does not mean those countries control American policy; it is straightforward an investment.

What would happen if China stopped buying US debt?

The Treasury would sell those securities to other investors instead. China holds about 3 to 4 percent of all US debt, so its absence would not create a shortage of buyers. The interest rate might rise slightly if demand fell, making borrowing more expensive, but the US would continue to function. China itself benefits from holding US debt, so it has little incentive to stop.

Does the US have to pay back all its debt?

Yes, but not all at once. When a Treasury security matures, the government repays that investor and can issue new securities to borrow more money. As long as investors are willing to lend and Congress raises the debt ceiling, the government can roll over its debt indefinitely. The concern is not whether the US will repay existing debt, but whether the total amount of debt becomes unsustainable relative to the size of the economy.

Who decides how much the US borrows?

Congress controls federal spending and tax policy, which together determine how much the government needs to borrow. The Treasury Department then executes the borrowing by issuing securities. The Federal Reserve influences interest rates but does not decide how much the government borrows. Ultimately, Congress decides whether to spend more than it collects in taxes, which creates the need to borrow.