, the world's biggest advertising group, downgraded its full-year like-for-like growth forecast to 1.5-3.0% from 3-5% after lower spending from tech clients caused its revenue in North America to decline in the second quarter.
Chief Executive Mark Read said the group delivered a "resilient" performance in the first half, with growth accelerating in all regions except the United States.
"(The U.S.) was impacted in the second quarter by lower spending from technology clients and some delays in technology-related projects," he said on Friday.
"China returned to growth in the second quarter albeit more slowly than expected."
The British company reported a 2.0% rise in like-for-like revenue less pass-through costs to 5.81 billion pounds ($7.39 billion) in the first half.
