• by Steve McClellan  @mp_mcclellan, March 15, 2012

Aegis Group media shop Carat issued a revised 2012 ad spending growth forecast Thursday, downgrading estimates for the U.S. by half a percentage point to 4.9%. It was the shop’s first revised forecast since last August. Global growth for the year was left unchanged at 6.0%.

Even with the downgrade, the shop’s U.S. estimate is more bullish than a revised estimate issued by Publicis Groupe’s ZenithOptimedia earlier in the week, which pegs U.S. ad-spending growth at 3.6% this year to about $160 billion. That was a slight upgrade, attributed to improving economic indicators.

Globally, ZO is slightly more optimistic than it had been -- but not as bullish as Carat. ZO slightly upgraded its worldwide growth estimate for the year to 4.8% for a total of $489.3 billion.

Carat, meanwhile, predicts that in 2013 global spending on digital advertising will overtake spending on newspapers for the first time, with digital spending increasing by more than 15%.

Globally, 2013 spending growth will reach 5.8% -- surprisingly strong, given the lack of special events in 2012 (Olympics and U.S. election cycle). That’s just two-tenths of a percentage off the pace of expected 2012 growth.

Western Europe will continue to slump this year, with slightly better results for 2013, per the Carat forecast. For 2012, Carat has downgraded the region’s estimated ad growth to 1.5%, half the previous forecast. Next year, results for the region are expected to rebound a bit, with 2.2% growth.

The Asia-Pacific region will continue to show robust growth this year and next, per the forecast, with a spending gain of 7.2% this year, followed by nearly 9% growth in 2013. The latter projection is an upgrade of about 2 percentage points versus Carat’s August forecast.

Spending in China will continue to grow sharply, up 15.4% this year and another nearly 15% in 2013.

Latin America will also continue to show double-digit growth this year and next, but Carat said the region will cool off slightly with spending that isn’t quite as high as it projected in August. For 2012, the region should be up close to 11% (down from the initially projected 13%) -- while next year spending in the region is expected to grow nearly 11% versus the 13% that was forecast in August.

Aegis CEO Jerry Buhlmann characterized the new Carat forecasts as “really encouraging. Not only do they confirm our expectation for robust growth through 2012, but they also show that the global market is expected to build on that strong performance in 2013 with further growth and in a year with no major events.”

Buhlmann added that the forecasts “underline our view that advertising spend is now regarded by most corporations as far less discretionary than ever before.”