Default Calendar: Which Payments Are Due When

The Treasury Department says it could start defaulting on U.S. obligations after Oct. 17. Other estimates suggest it could be weeks until the U.S. reaches that point. Key dates that investors and policy makers are watching:

Oct. 17

What happens: The U.S. will exhaust emergency measures it has used since reaching the $16.7 trillion debt limit in May. By this date, it expects to have only $30 billion of cash and any incoming tax revenue to pay obligations. Early that afternoon, the government rolls over, or replaces, $120 billion in maturing debt.

Why it matters: Missing the publicly established deadline could rattle investors and diminish the appetite for some debt, as the potential for a default draws nearer.

Oct. 22

What happens: The first day the government could start missing payments, according to analysts at the Congressional Budget Office and Bipartisan Policy Center.

Why it matters: Passing this date might be seen in markets as the start of a more serious crisis.

Oct. 23

What happens: $12 billion in Social Security payments due

Why it matters: It is the first of several large upcoming payments. The Obama administration hasn’t said publicly whether it is feasible to pay Social Security recipients while skipping other payments.

Oct. 24

What happens: A rollover of at least $93 billion in maturing debt, according to the Bipartisan Policy Center.

Why it matters: Investors could expect higher interest rates on some debt, raising the cost to the U.S.

Oct. 28

What happens: Payment due on $3 billion in federal employees’ salaries

Why it matters: The partial government shutdown has created doubts about which employees will be paid and when. A monthlong shutdown is unlikely to delay the date of a U.S. default by more than a couple of days.

Oct. 30

What happens: $2 billion in payments due to Medicaid providers

Why it matters: Missing the payment would cast doubt about the ability to maintain support for the health-care program in the near term.

Oct. 31

What happens: $6 billion interest payment due; rollover of at least $89 billion in maturing debt.

Why it matters: It will test whether the government would prioritize payments to debtholders over other obligations. Oct. 31 is also the last date of CBO’s range for when the government would still have cash available to keep paying bills.

Nov. 1

What happens: $55 billion in Medicare, Social Security and military payments due

Why it matters: By this date, the Bipartisan Policy Center estimates the government would have exhausted any remaining reserves and would have to default on other payments.