Google Grilled On Ad Business Dominance By U.S. Senate Panel

“As that business has grown, so too have complaints that Google – which both operates the ad selling and buying platforms, and sells its own inventory through those platforms -has conflicts of interest and has manipulated or rigged online ad technologies and auctions to favor its own interest,” Lee said.

He and others pressed Harrison on advertiser complaints that Google was opaque where ad dollars went; specifically how much went to publishers and how much to Google.

Harrison, who took over as head of Google’s corporate development in 2012, argued that the ad tech ecosystem was crowded and competitive, with Amazon.com Inc and Facebook Inc , AT&T, Comcast and others among Google’s powerful rivals, and that the price of placing an ad had fallen.

The tech giant made a series of purchases, including DoubleClick and AdMob, to help make it the dominant player in online advertising.