The US government has shown support for the small Canadian firm i4i in its ongoing patent infringement lawsuit against Microsoft.
The US solicitor general filed the amicus curiae brief in support of the company on Friday. A number of other parties have also filed briefs in support of i4i, including General Electric, 3M, Boston Scientific, the Intellectual Property Owners (IPO) association and a number of venture capital firms.
The case centres around XML tagging features of Word 2003 and Word 2007 which i4i said infringed on patent number 5,787,449 which covers a "method and system for manipulating the architecture and the content of a document separately from each other".
In May 2009, Microsoft was found guilty of infringement, fined $200m (around £128m at the time) and ordered to strip the functionality from its software. The company appealed the court's decision but lost the appeal in December 2009.
In light of the defeat, Microsoft filed a second appeal in January 2010 requesting that the case be reheard by a panel hearing, as well as an en banc review. In March, the panel's decision upheld the infringement ruling against Microsoft.
In November 2010, the US Supreme Court agreed to hear another appeal from Microsoft.
A number of companies also filed amicus briefs in support of Microsoft, including the computer and communications industry, the CTIA, Google, Apple, SAP and EMC.