NEW YORK: Interpublic's Magna Global unit downgraded its outlook for US ad spending this year to 2.9% from an initial forecast of 3.1%.

Magna Global now expects US ad spending to reach roughly $173.1 billion in 2011 (excluding political and Olympic advertising).

Alex Feldman, manager of global forecasting for Magna Global, attributed the downgrade to slowing growth in the manufacturing sector, as well as disappointing retail sales.

Magna Global does not include PR spend in its forecast. However, other reports forecast strong growth ...