Google served a subpoena to Microsoft over three months ago, seeking documents regarding Bing.
A federal judge asked Microsoft on Friday to let him know how big of a burden it would be for the company to provide documents requested by long-time rival Alphabet's Google, in a US antitrust lawsuit against Google.
The search and advertising giant had asked the judge to compel Microsoft to turn over documents, citing its failure to comply with a subpoena, according to a court filing unsealed late Thursday.
"In terms of does this request meet the general definition of relevancy? The answer is yes," said Judge Amit Mehta of the US District Court for the District of Columbia at a hearing on Friday.
Google served a subpoena to Microsoft more than three months ago, seeking documents regarding Microsoft's Bing search engine as well as its Internet Explorer and Edge but has not received them, the filing said.
Google says some of the documents might shed light on whether Microsoft was actually restrained from competing with Google, or whether it simply failed to compete successfully.
"In particular, there are nineteen Microsoft employees who held important positions relating to activities at the core of this case but whose files Microsoft refuses to commit to search at this time," Google said in the filing.
Google's search engine is the market leader by far while Bing's share is in single digits. Google also has a browser, Chrome.
Microsoft, also in a filing late on Thursday, said Google's additional requests bring the total number of custodians, whose files Microsoft will have to search, to 55.
According to Google, these executives covered issues at the core of the case, including the development and distribution of Microsoft's various search engines, Microsoft's search advertising business, and Microsoft's effort to market devices that would give it more search access points beyond the Windows desktop.
The Justice Department sued Google in October, kicking off a spate of federal and state antitrust lawsuits against both Google and Facebook. The federal case against Google and a broader state case have been consolidated for purposes of trial preparation.