Google has diluted its controversial Comparison Shopping Service (CSS), which critics say encourages the creation of “fake” price comparison sites, with one agency calling it “a feeding frenzy” among ad agencies and ad tech firms.

Sky News reported that after an attempt to encourage price comparison sites to bid for places in its Shopping box didn’t go to plan, for the last four months Google had been encouraging ad firms to build price comparison shopping sites for it to present in the Google Shopping box. The company offered incentives to retailers that passed their adverts through CSS, which then Google showed the names of the CSSs in the Google Shopping box, giving the impression of a thriving comparison shopping marketplace.

Google’s CSS launched in June 2018. Within four months, 120 sites turned up to the scheme, and then to the surprise of the participating agencies, Google changed the terms of the agreement. In an email, Google outlined that it would no longer be giving retailers a rebate of 30% on their ad spend, worth up to £27,000 a month. Instead, starting November 1, the rebate would be 5%.

Sky News found out that Google has slashed the incentives it gives all but the biggest retailers, leaving many small agencies feeling betrayed.

However, a site operator told Sky News the sites were not designed to be used for shopping, claiming it’s “an advertising system that looks like price comparison”.

The search giant is under pressure after it was fined a record $2.7 billion in 2017 by the European Commission, having been accused of “skewing” search results in favour of its shopping ads.

If Google fails to please the Commission, it could be liable for non-compliance payments of up to 5% of the average daily worldwide turnover of Alphabet, Google’s parent company, backdated to the start of non-compliance.