market as Google search ads but not ads shown on Amazon or other platforms where there is user overlap.
This argument misses the point. SVP search ads offerings are included in the search ads market. They target their users who express real-time intent with a query. Nor is there anything inconsistent about treating search ads and ads on other platforms, like social media, as distinct products even though they have overlapping audiences. Marketers use them as complements to fulfill their ultimate objective: to drive sales. FOF ¶¶ 221, 225.
Sensitivity to Price Changes. U.S. Plaintiffs argue that advertisers do not substitute away from search ads, even in the face of price hikes. Google says otherwise. It contends that advertisers care more about ROI or return on ad spend (ROAS) than any particular advertising channel, and that they move ad spend across different channels to maximize their ROI. For example, Google points out that advertisers increasingly are using tools like its own Performance Max, which helps advertisers optimize their ad spend to yield the best ROI. GFOF ¶¶ 1009–1013; FOF ¶ 229.
But Google’s focus on ROI misses the forest for the trees. Products are reasonably interchangeable only if “significant” substitution occurs in response to a price increase. See Ohio v. Am. Express Co., 585 U.S. 529, 543–44 (2018). To be sure, advertisers did testify to shifting spend to maximize ROI. But none said that they have “significantly” shifted ad spend away from search ads. In fact, the opposite is true. Advertisers uniformly said that they would not substitute search ads for another ad type absent some campaign-level reason to do so. FOF ¶¶ 230–231; see Staples, 970 F. Supp. at 1074 (courts look to “whether and to what extent purchasers are willing to substitute one for the other”). To the extent that ad dollars are increasingly being spent on other channels, that change reflects the ballooning of the digital advertising market as a whole.
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