How a US government shutdown works

By Ryan Hogan, founder of Tungsten LLC. Published September 22, 2026.

A government shutdown is easy to describe and easy to misunderstand. The government does not close. Most of what it spends keeps flowing, air traffic control keeps operating, and Social Security checks keep arriving. What stops is the part of federal activity that depends on Congress passing spending bills each year.

Knowing which part that is explains why shutdowns disrupt some things immediately, leave others untouched, and matter to markets mainly through the data they delay.

Two kinds of federal spending

Federal spending divides into two categories, and only one of them is exposed.

Mandatory spending flows from laws already on the books. Social Security, Medicare, Medicaid and interest on the debt fall here. The authority to spend does not expire, so a funding lapse does not stop the payments. This is the larger share of the budget.

Discretionary spending must be approved each year through appropriations bills. Federal agencies, the military, national parks, food inspection, statistical agencies and most of what people picture as "the government operating" fall here.

When the fiscal year ends on September 30 and no appropriation is in place for the next one, the legal authority to obligate discretionary funds lapses. The Antideficiency Act prohibits agencies from spending money they have not been given, so they must stop.

Excepted and non-excepted work

Agencies plan for this in advance, classifying employees by whether their work may continue during a lapse.

Excepted employees keep working. The categories include protection of life and property, and functions funded by something other than annual appropriations. Air traffic controllers, active-duty military, federal law enforcement, and hospital staff at veterans' facilities keep reporting. They work without pay during the lapse, and under a 2019 law they receive back pay afterward.

Non-excepted employees are furloughed. They are barred from working, including from checking email, until funding returns.

The split is why a shutdown looks uneven from outside. The visible, safety-related functions continue, while permitting, routine inspections, research, and public-facing services stop.

What stops that markets notice

The economic effect of a shutdown is usually modest and temporary, since most of the furloughed work resumes and the pay arrives later. Markets have historically treated them as noise.

The part that does matter is information. The Bureau of Labor Statistics and the Census Bureau are funded by annual appropriations, so during a lapse the jobs report, the consumer price index and trade data are not published. Private data continues, but the official statistics that set the terms of every economic argument do not appear.

That creates a specific problem. The Federal Reserve sets policy against incoming data, and a lengthy lapse means it meets with less of it. The delay compounds, since surveys not conducted on schedule cannot always be reconstructed later.

Other market-relevant functions pause too. The Securities and Exchange Commission operates with a skeleton staff, so registration statements sit, and companies planning to go public wait.

How they end, and the vocabulary of ending them

A shutdown ends when Congress passes and the president signs a funding measure. Three forms show up.

A continuing resolution extends the previous year's funding for a set period. Most funding gaps end this way, which is why the same fight recurs a few months later.

An omnibus bill bundles multiple appropriations into one large measure, usually when individual bills cannot pass separately.

Reconciliation is a different tool entirely, and the two get confused. Reconciliation applies to taxes, mandatory spending and the debt limit, and lets certain bills pass the Senate by simple majority. It is not how annual appropriations get enacted, though it shapes the fiscal backdrop they operate in.

What history shows

There have been several funding gaps since the modern budget process began in the 1970s, and a handful long enough to matter.

The shutdown that began in December 2018 ran 35 days, the longest on record. The Congressional Budget Office estimated it reduced economic output during the affected quarters, with most of that recovered afterward and roughly $3 billion permanently lost. The 2013 shutdown lasted 16 days and produced a similar pattern: a visible dip, followed by recovery.

The market reaction in both cases was muted. Equities were roughly flat to higher across the 2018 episode. This is the consistent lesson, and it holds for the same reason each time: the spending is deferred rather than cancelled, and the interest payments that would alarm bondholders are mandatory, so they never stop.

The exception worth separating is the debt limit, which is a different mechanism. A shutdown means the government lacks authority to spend. A debt limit breach would mean it lacks authority to borrow to pay obligations it already owes. The first is disruptive and routine. The second has never happened, and the consequences are not comparable.

The terms involved

Appropriations provide agencies their legal authority to spend. A furlough is unpaid leave with the job intact. Reconciliation is the majority-vote budget process for taxes and mandatory spending. A shutdown is what happens when appropriations lapse.

The archive has the questions these came from, and the glossary defines each one.