In yet another major blow to U.S. television networks and stations, General Motors, one of the country's biggest ad buyers, has canceled half its TV commercials during the second quarter, Bloomberg News reported today (Wednesday), citing unnamed media analysts.

Bob Flood, an executive at media buyer Optimedia International, told the wire service: "Any advertiser cutting back right now would make networks nervous, but an advertiser as big as GM cutting back is especially bad."

Source: Studio Briefing