The U.S. borrows from domestic investors, foreign governments, and its own trust funds

The United States borrows money by selling Treasury securities — bonds, notes, and bills that promise to pay back the money with interest. Anyone can buy them: individual Americans, pension funds, banks, foreign governments, and central banks. The largest single holder is the Federal Reserve, which bought Treasuries as part of its monetary policy. After that come domestic mutual funds and retirement accounts, then foreign governments led by Japan and China.

When you hear that the U.S. owes money "to China" or "to Japan," it means those countries' central banks or investment funds hold Treasury securities. They lend because Treasuries are considered the safest investment on earth — backed by the U.S. government's power to tax and print currency. The interest rate the government pays depends on how long you lend for and how much risk investors perceive at that moment.

Key Takeaways

  • The Federal Reserve holds the largest share of U.S. debt, followed by domestic pension funds, mutual funds, and individual Americans.
  • Foreign governments and central banks, particularly Japan and China, hold a significant portion but less than half of total U.S. debt.
  • The U.S. government borrows by selling Treasury securities directly to investors through auctions run by the Department of the Treasury.
  • Interest rates on Treasury securities change based on how long the loan lasts and how much risk investors see in the economy at that time.
  • Social Security and Medicare trust funds lend to the government when they collect more in taxes than they pay out in benefits.

How the Treasury auctions work

The Department of the Treasury holds regular auctions where it sells new securities. These happen on a schedule: Treasury bills (short-term, under one year) auction weekly, notes (two to ten years) auction monthly, and bonds (20 to 30 years) auction less frequently. Anyone with a brokerage account can bid, as can banks, foreign central banks, and institutional investors.

At each auction, the Treasury announces how much it wants to borrow and investors submit bids saying what interest rate they will accept. The Treasury fills bids from lowest interest rate (cheapest for the government) to highest until it has sold the amount it needs. This is why interest rates on Treasuries move with market conditions — if investors think the economy is risky, they demand higher rates before they will lend.

The Federal Reserve's role as the largest holder

The Federal Reserve owns more Treasury securities than any other single entity. It accumulated this holding over decades, but especially after 2008 and again after 2020, when the Fed bought Treasuries as part of its effort to lower interest rates and support the economy. These purchases are called quantitative easing.

When the Fed holds Treasuries, the interest payments the government makes to the Fed flow back into the U.S. Treasury as revenue — so the government is, in effect, paying interest to itself. This is different from when a foreign government or a pension fund holds the debt; those entities keep the interest payments. The Fed can also sell Treasuries if it wants to remove money from the economy, which it began doing in 2022.

Domestic holders: pension funds, mutual funds, and individuals

Most U.S. debt is held domestically. Pension funds — both public (like CalPERS, the California Public Employees' Retirement System) and private — hold large amounts because Treasuries are safe and predictable. Mutual funds and exchange-traded funds that track bond indexes hold Treasuries on behalf of millions of individual investors. Many Americans own Treasury securities without knowing it, through their 401(k) or IRA.

Individual Americans can buy Treasuries directly through TreasuryDirect, a website run by the Department of the Treasury. You can purchase as little as $100 and hold the security until it matures. Banks also hold Treasuries as part of their required reserves and as a safe place to park deposits.

Foreign governments and central banks

Japan and China together hold roughly 2 trillion dollars in U.S. Treasury securities, though the exact amount changes monthly. Japan's central bank and government pension fund hold Treasuries partly because the U.S. is Japan's largest trading partner and partly because Treasuries are the safest long-term investment available. China accumulated its holdings over decades as it ran trade surpluses with the United States.

Foreign governments hold Treasuries for several reasons: they need a safe place to keep their foreign currency reserves, they earn interest, and Treasuries are liquid — straightforward to sell quickly if they need cash. However, the idea that foreign governments could "call in" U.S. debt is a misunderstanding. Treasury securities have maturity dates; when they mature, the government pays them back. Foreign holders cannot demand early repayment any more than you can demand a bank pay off your mortgage before the term ends.

Social Security and Medicare trust funds

When Social Security collects more in payroll taxes than it pays out in benefits — which it did for decades — the surplus went into the Social Security Trust Fund. That fund lends the surplus to the federal government by buying Treasury securities. The same happens with Medicare's Hospital Insurance Trust Fund when it runs a surplus.

These trust funds now run deficits, meaning they pay out more than they collect. As they do, they sell the Treasuries they hold to cover the difference. This is not a crisis or a sign of mismanagement; it is how the system was designed to work. The trust funds are drawing down their reserves, and eventually Congress will need to adjust payroll taxes, benefits, or both to keep the programs solvent long-term.

Why the U.S. can borrow so much

The U.S. government can borrow more than most countries because the dollar is the world's reserve currency and because investors believe the U.S. will repay its debts. The government has never defaulted on its obligations. Investors also know the U.S. can raise taxes or cut spending to service its debt, and that it can print dollars if needed (though doing so causes inflation).

Interest rates on Treasuries reflect this confidence. Even when U.S. debt is very high, interest rates remain low compared to what other countries pay. If investors lost confidence, interest rates would spike, making it much more expensive for the government to borrow. This has not happened, but it is the ultimate constraint on how much the government can borrow.

Frequently Asked Questions

Can a foreign country refuse to lend to the U.S. anymore?

Yes, but it would be unusual. Countries hold Treasuries because they are safe and earn interest. If a country stopped buying, it would straightforward mean fewer Treasuries sold at that auction. The government would still find buyers — either other foreign investors, domestic investors, or the Federal Reserve. Interest rates might rise if demand fell, making borrowing more expensive.

What happens if the U.S. defaults on its debt?

The U.S. has never defaulted. If it did, investors would lose confidence in all Treasury securities, interest rates would spike, and the government would struggle to borrow for anything. It would also damage the dollar's status as the world's reserve currency. Congress has always raised the debt ceiling before default became possible.

Does the U.S. owe money to the Federal Reserve?

Technically yes — the Fed holds Treasuries like any other investor. But the interest payments flow back to the Treasury, so it is more accurate to say the government owes money to itself. The Fed can sell its holdings if it wants to tighten monetary policy, which it has done in recent years.

Why would China or Japan keep lending if the U.S. debt is so high?

Because Treasuries are still the safest investment available and earn interest. China and Japan also benefit from a strong U.S. economy and stable dollar. Selling all their Treasuries at once would crash the value of what they still hold and disrupt global trade. They have more incentive to keep lending than to stop.

Can I buy U.S. Treasury securities if I am not a U.S. citizen?

Yes. Foreign individuals and entities can buy Treasuries through brokers or directly through TreasuryDirect if they have a U.S. tax ID number. The process is straightforward because the U.S. wants to attract foreign investment in its debt.