Guideline: Longest U.S. Government Shutdown Poised To Squeeze Ad Market.

The U.S. entered the longest federal government shutdown in history on Nov. 5, setting off a wide range of expected effects on advertising spending, according to a new Guideline analysis that examines how past shutdowns have influenced the market.

Analysts said the current shutdown offers little historical precedent, making its economic trajectory uncertain. They outlined two likely phases of impact: the immediate period during the shutdown and longer-term effects as disruptions move through businesses and the broader economy.

In the near term, advertising spending is expected to remain relatively stable. Past shutdowns show that ad spending within the same quarter generally continues at its existing pace and tracks closely with market averages, even when compared with growth rates from the preceding quarter.

But signs of weakening are emerging in specific categories as revenue losses begin to translate into reduced budgets. Analysts said they expect the ad market to soften beginning in the first half of 2026.

Airlines are likely to feel early pressure after the Federal Aviation Administration moved to pull back on flights, leading to a drop in travel volume. Still, airline advertisers are keeping spending elevated through the end of the year to support forward bookings, hoping the shutdown will end and holiday travel will rebound.

Some travel-related categories may benefit from shifting consumer behavior. Increased demand for rental cars and hotels could offset declines in airline spending if more travelers choose to drive rather than fly. Cruises, which are already pacing ahead of last year based on forward booking data, may also see gains.

The pharmaceutical sector faces another consequence of the shutdown. The Food and Drug Administration has approved 32 novel drugs so far this year, compared with the typical annual range of 50 to 60. Novel drug approvals, which often carry significant consumer marketing support, are projected to drop by 10 to 20 in 2026 because of delays tied to the shutdown. The slowdown could lead to a “significant decline in ad spending as early as H1 ’26,” according to the analysis.

While the long-term economic effects remain difficult to predict, analysts said the advertising sector is likely to show signs of strain before broader economic indicators register the full impact of the shutdown.