One of Google's biggest rivals – Yahoo – has confirmed that it is running tests to see if it should use Google's search results on its websites, something that it previously limited to Microsoft's Bing search engine.
The testing follows a renegotiation in April of the contract between Microsoft and Yahoo, which allows 49% of Yahoo ads to come from other ad firms, such as Google.
The terms of the renegotiation included amendments in two core areas, which gave Yahoo increased flexibility to enhance the search experience on any platform, since the partnership is non-exclusive for both desktop and mobile.
Yahoo will continue to serve Bing ads and search results for a majority (51%) of its desktop search traffic, but Microsoft became the exclusive agent for ads delivered by the company's Bing Ads platform, though Yahoo continues to be the exclusive provider for its native Gemini ads platform.
"As we work to create the absolute best experiences for Yahoo users, from time to time, we run small tests with a variety of partners including search providers," a Yahoo spokesperson confirmed to the blog Search Engine Land. "There is nothing further to share at this time."
In June, Yahoo announced the availability of independent viewability and fraud measurement for display and video advertising on Yahoo owned and operated properties, as well as media purchased across its programmatic buying platform.
A recent report from eMarketer forecast that Microsoft and Yahoo combined would own 6.5% of the $81 billion search market globally in 2015, while Google, the search leader, was expected to take a 54.5% of the global market this year.
Digital ad spending worldwide is expected to hit more than $170 billion this year, according to the report, with search ads accounting for $81.59 billion worldwide, an increase of 16.2% over 2014.
[Read more about the fight between Google and Yelp.]
The report also projected that by 2019, search ad spending will reach more than $130 billion globally, still growing at nearly 10% year-over-year.
A June report from Kantar Media found ad spending for paid search, which reflects text ads on the Google and Bing search engines, rose 7% in the first quarter of 2015, with automotive, financial service, media, and retail advertisers leading the way.
However, expenditures for online display, which is based upon desktop display ads only, and excludes video and mobile ad formats, declined 8.7% compared with last year.
The report noted that the main factors contributing to the decline were lower cost per thousand impressions (CPMs) and reduced page traffic, with the latter likely being attributable to mobile devices siphoning some desktop usage.