Elon Musk is back on the war path with the advertising industry, pushing for some US states to consider criminal prosecution of members of the Global Alliance for Responsible Media (GARM) as the US House Judiciary Committee investigates whether companies involved in the WFA initiative are in fact colluding to block ad spend to conservative media.

"Having seen the evidence unearthed today by Congress, X has no choice but to file suit against the perpetrators and collaborators in the advertising boycott racket," Musk posted on X. The billionaire entrepreneur and Tesla founder bought the platform (formerly Twitter) in 2022 and has since seen advertising revenue plunge as brands pause spend amid growing concerns for brand safety.

A hearing on Thursday saw the committee grill Unilever and Group M chiefs over allegations that members of GARM, an initiative created by the World Federation of Advertisers (WFA) to improve online safety for consumers and advertisers (and more recently, provide a framework for reducing carbon emissions in the media supply chain), had colluded to silence conservative speech and platforms in violation of antitrust law.

Representatives from the both companies sit on GARM's Steer Team alongside members from P&G, Unilver, Mars, Diageo, Mastercard, GroupM, 4As, ISBA, and the US Association of National Advertisers (ANA). Other members include the IAB, Havas Media, dentsu, Meta, Microsoft, Omnicom Media Group, Publicis Media, Snap, Spotify, TikTok, UM and the Australian Association of National Advertisers (AANA). X itself only just rejoined the group this month after drifting from the initiative following Musk's takeover.

A report issued by the Committee details email conversations between members that discuss the demonetisation of sites of conservative media outlets including Daily Wire, Breitbart, and X. However, Loyola University Chicago School of Law competition law professor Spencer Waller testified to the committee that the evidence presented did not amount to collusion

The committee also heard testimonies from far-right commentator and The Daily Wire co-founder, Ben Shapiro, as well as Unilever USA president Herrish Patel, and GroupM global chief executive officer, Christian Juhl.

"In reality, GARM acts as a cartel. Its members account for 90% of ad spending in the United States, almost a trillion dollars. In other words, if you're not getting ad dollars from GARM members, it's nearly impossible to run an ad-based business. And if you're not following their preferred political narratives, the ones that Kara Swisher and Dianne Feinstein would follow, you will not be deemed brand safe. Your business will be throttled," Shapiro told the hearing.

In his testament, GroupM's Juhl argued that Group M and other GARM are concerned only with brand safety, and in mitigating risk associated with sensitive content.

"GroupM has no interest in impinging on anyone's right to speak or publish their points of view. One of the most exciting developments in technology in recent years has been the ease with which it is now possible for individuals and small companies to build content-based businesses and audiences using the web and social media," Juhl told Congress.

"However, free and robust speech also means that the internet contains controversial content. We believe companies also have the right to choose where they do and don't place their advertisements. It is a legitimate choice for companies to avoid placing advertisements in environments that may produce suboptimal or even negative returns on their investment."