Not only did Amazon.com Inc., No. 1 in the Internet Retailer 2018 Top 500, set a company record on Cyber Monday for the most products sold in a single day, but the retail giant’s fast-growing advertising business appears to have had its biggest revenue growth during the five-day stretch that runs from Thanksgiving to Cyber Monday, according to a new report from digital marketing firm Kenshoo.

Thanks in part to the flood of traffic to Amazon’s site and app, marketers boosted their spending on Amazon’s ads. Amazon advertising among Kenshoo clients during the key holiday shopping days of Thanksgiving, Black Friday and Cyber Monday was up to 3.5 times greater than the average daily spending on Amazon ads during the pre-holiday period of October.

And, in a sign of how quickly Amazon’s advertising business is growing, Kenshoo clients spent 2.2 times more on Amazon’s Sponsored ads—such as Sponsored Products and Sponsored Brands (formerly known as Headline Search Ads)—on Cyber Monday than they did on average during this year’s Prime Day summer shopping event.

That spending paid off, says Margo Kahnrose, Kenshoo’s vice president of marketing, noting that Amazon Advertising-driven sales rose threefold on Black Friday compared to the pre-holiday period.

That helps explain why 80% of Kenshoo clients that advertise on Amazon plan to boost their spending on the platform next year, according to a recent survey by the vendor. Another survey, conducted by Internet Retailer in August, found that 26.2% of retailers currently advertise on Amazon and 37.7% expect to advertise on Amazon in 2019.

Paid search spending pays off

Beyond Amazon, Kenshoo clients’ paid search spending rose 20% on Thanksgiving Day year over year and 16% on Black Friday year over year. That’s a reversal from last year when Black Friday was a bigger growth day than Thanksgiving.

Compared with last year, the cost per click for search ads dropped during those two shopping days with the average price of a click decreasing 8% year over year on Thanksgiving and 10% on Black Friday. That’s roughly in line with the Kenshoo Q3 2018 Quarterly Trends Report that reported a 15% decline in the overall cost per click among search ads in the third quarter, thanks in large part to retailers shifting more of their dollars to lower-priced mobile search ads.

Kenshoo clients boosted their spending on mobile search ads by 44% on Thanksgiving and 43% on Black Friday. In part, that was a reflection of the mobile cost per click on Thanksgiving costing 41 cents, a 51.9% jump from 27 cents in the pre-Thanksgiving period (Nov. 1-21). On Black Friday, the average cost per click for mobile was 50 cents, an 85.2% increase over the pre-Thanksgiving period.

However, those premium prices paid off as conversion rates from mobile search ads jumped to 5.6% on Thanksgiving (up from 4.0% during the pre-Thanksgiving period) and 8.3% on Black Friday.

Paid search leaders

J.C. Penney, No. 31 in the Internet Retailer 2018 Top 500, dominated paid search clicks on Black Friday, while Best Buy, No. 8, led the way on Cyber Monday, according to an analysis of unbranded keywords by Kantar Media.

J.C. Penney had an 18.4% click share on Black Friday, more than double the runners-up, Macy’s, No. 6, (7.6%), Sears, No. 24, (7.2%), Kohl’s, No. 18, (7.0%) and Verizon (5.9%)

Best Buy had a 14.3% click share on Cyber Monday, ahead of Verizon (10.6%), Target, No. 17, (8.1%), Apple, No. 2, (7.3%), Office Depot, No. 14, (6.3%).

The analysis is based on Kantar’s analysis of 2,500 popular retail product keywords across desktop and mobile search from Nov.23 to Nov. 26.

Across the entire period, Walmart led all advertisers in Product Listing Ad clicks, while Amazon was the top text ad advertiser.

Here are the top five PLA advertisers, in terms of desktop clicks:

1. Walmart, 10.8%
2. Amazon, 5.0%
3. Kohl’s, 4.4%
4. Macy’s, 3.4%
5. Target, 3.0%
6. Wayfair 3.0%

Here are the top five PLA advertisers, in terms of mobile clicks:

1. Walmart, 6.7%
2. Jet, 4.2%
3. Bed Bath & Beyond, 3.4%
4. Kohl’s, 3.0%
5. Etsy, 2.8%

Here are the top five text ad advertisers, in terms of desktop clicks:

1. Amazon, 6.9%
2. J.C. Penney, 5.8%
3. Macy’s, 2.2%
4. Wayfair, 1.9%
5. Overstock, 1.5%
6. Office Depot, 1.5%
7. Fitbit, 1.5%

Here are the top five text ad advertisers, in terms of mobile clicks:

1. Amazon, 12.6%
2. J.C. Penney, 3.7%
3. Macy’s, 2.6%
4. Wayfair, 1.4%
5. Hayneedle, 1.3%
6. Lowe’s, 1.3%

Notably, Walmart moved away from text ads in its paid search strategy, which is why it was not present among the top text ad sponsors for desktop or mobile search.

Social media spending soars

The cost per thousand impressions (CPM) on social media ads skyrocketed on Thanksgiving and Black Friday, Kenshoo’s data shows. Prior to Thanksgiving, the CPM among Kenshoo clients was $6.09. But on Thanksgiving that rate jumped 40.9% to $8.58, and on Black Friday, it nearly doubled to $12.02.

Despite the increased cost, consumers’ engagement rate with those social media ads, which measures website clicks, shares, likes and other interactions with the ad, had modest growth from 2.7% prior to Thanksgiving to 2.9% on Thanksgiving Day and 3.1% on Black Friday.