UK marketing services giant WPP and the country's biggest supermarket chain Tesco are both taking £1 ($1.9, €1.4) out of every £8 spent in their respective shops.
Latest figures from Nielsen Media Research shows advertisers spend £1.1 billion annually through Sir Martin Sorrell's group, out of a total UK ad spend budget of £8.7bn.
WPP announced a 15% rise in 2004 profits to £546m last week and a 5% increase in billings to £19.6bn.
WPP, which owns big names JWT, Ogilvy & Mather, and Young & Rubicam, has a 12.7% share of total UK billings. Its biggest rivals, Omnicom, Publicis Groupe and Interpublic, control just over 27% between them.
Tesco's market share in the three months to the end of February was 29.2% and in the four weeks of February it was 29.9%, up from 27.3% a year earlier. It is likely to break the 30% barrier next month, when it will also announce profits of more than £2bn.
Data sourced from Brand Republic (UK); additional content by WARC staff