Google reportedly paid Apple one billion dollars (£700m) in 2014 to keep its search bar installed as the default option on iPhones.
Details of various Google financial arrangements have been leaked from court documents stemming from a case with Oracle, the creator of Java, which has accused the search giant of including some of its proprietary code in its Android mobile operating system.
The one billion dollar deal that was allegedly put in place between Google and Apple also saw a percentage of the advertising revenue from search traffic generated by iPhones going to Apple.
The court transcript that referenced the deal has now reportedly vanished from electronic court records.
All web searches that take place on iOS devices, namely the iPhone and iPad, are done using Google, with its search engine embedded into the mobile devices' interface.
Both Apple and Google have so far declined to comment.
Earlier this week it was also revealed that Google removed more than 780 million ‘bad’ adverts from its sites last year.
"Some bad ads, like those for products that falsely claim to help with weight loss, mislead people," the firm said in a blog post.
"Others help fraudsters carry out scams, like those that lead to 'phishing' sites that trick people into handing over personal information.
"Through a combination of computer algorithms and people at Google reviewing ads, we're able to block the vast majority of these bad ads before they ever get shown."
In 2012, Apple removed the Google Maps app from iPhones with no notice given to the company or its users. It replaced the app with its own Apple Maps which initially had some significant teething problems much to the chagrin of iPhone users.