Hit with a 2.4-billion-euro ($2.8 billion) fine three years ago by the European Commission for the offence, Google subsequently offered to allow competitors to bid for advertising space at the top of a search page to channel traffic to their sites. Rivals however have said the proposal was ineffective and since then have urged EU antitrust chief Margrethe Vestager to sanction Google for not complying with her ruling. The latest study by consultancy Lademann & Associates covered Axel Springer"s SPRGn.DE price-comparison shopping service Idealo, British company Kelkoo, France"s LeGuide and others in 21 European countries. ADVERTISEMENT “It (Google’s proposal) has further strengthened Google’s position on the national markets for comparison shopping services and has entrenched its dominance in general search,” said Thomas Hoppner, author of the study and adviser to several Google foes. “This is not because the Commission imposed the wrong remedy. It is because Google’s chosen compliance mechanism fails to comply with the remedy imposed,” he said. Hoppner called the Commission to either force Google to come up with a more effective solution or warn the company for breaching its order. ADVERTISEMENT The Commission said it was monitoring the market to assess the effectiveness of Google’s proposal. Google said the figures in the study ignore the facts and the Commission’s reasoning in its decision. “The remedy has worked successfully for three years, generating billions of clicks for more than 600 comparison shopping services, and is subject to intensive monitoring,” a spokeswoman said.