As part of an agreement with Congress to receive financial assistance from the government, U.S. auto makers have promised to "dramatically" cut down on their number of dealers and brands, Dow Jones reported Wednesday.

The cuts mean marketing spending by General Motors Corp., Ford Motor Co. and Chrysler Corp., which together make up a bulk of the second-largest advertising category in the nation, will drop substantially, according to Dow Jones.

The U.S. advertising market is currently seeing the biggest downturn since 2001, which was the worst year for advertising since 1970, Fitch Ratings announced Wednesday. The ratings group also said it expects deterioration in the ad market to last into 2010, according to the Dow Jones article, posted by CNN Money.

GM announced it plans to lower its brand count from 48 to 40, and will also reduce its number of dealers from 6,450 to 4,700 by 2012. The company will also cut its ad budget by about one-fifth, according to Dow Jones.

"This would be particularly difficult for local TV stations and newspapers, which see roughly 12% and 7% of their revenue from local and regional auto dealers respectively," Morgan Stanley analyst Benjamin Swinburne told Dow Jones.

Ford and Chrysler both spent 22 percent less in advertising this year, through July 2008, than they did in the same period in 2007, according to Nielsen Monitor-Plus. GM lowered its ad spending by 6 percent, Dow Jones reported.

Swinburne said top ad agencies such as Omnicom Group and Interpublic Group rely on auto makers for 14 percent of their sales, and are likely to also suffer from brand reductions, according to Dow Jones.