More than a quarter of advertisers are planning to cut spending on Elon Musk’s X over concerns about the social media platform’s content and trust in the information disseminated, according to new global research.

Advertising revenue flowing to X has been in freefall since Musk bought the site, then known as Twitter, for $44bn (£38bn) in October 2022, claiming it had not lived up to its potential as a platform for “free speech”.

However, Musk’s erratic and controversial behaviour on X, where he has almost 200 million followers, has fuelled a backlash from advertisers who have cut back or stopped running promotions there.

Research by data firm Kantar, based on interviews with 18,000 consumers and 1,000 senior marketers around the world, has found that 26% of marketers are planning to cut back ad spend on X in 2025.

“Marketers are brand custodians and need to trust the platforms they use,” said Gonca Bubani, a director at Kantar. “X has changed so much in recent years and can be unpredictable from one day to the next. It is difficult to feel confident about your brand safety in that environment.”

Kantar has been conducting the study annually for several years. The figures for 2024 show that the exodus is rapidly gathering pace, with 14% of marketers saying they would pull budgets this year.

Figures from eMarketer highlight the rapid commercial decline of the platform in recent years, with the company’s global revenues peaking in 2021 at $4.46bn, of which the UK accounted for $366m, about 8% of the total.

In 2022, global revenues dropped to $4.14bn. Since the world’s richest man took over the site at the end of that year, they have more than halved, with annual revenue forecast to fall to $1.9bn by the end of this year, with UK revenues predicted to be just $160m.

“Advertisers have been moving their marketing spend away from X for several years,” said Bubani. “The stark acceleration of this trend in the past 12 months means a turnaround seems unlikely.”

The advertiser exodus is just one in a run of commercial headaches for Musk – who has come in for criticism over posts relating to topics including antisemitism, the recent riots in the UK and US politics – the latest of which is a ban on X in Brazil.

Brazil is one of its biggest global markets, with more than 20 million users. But Brazil’s supreme court voted unanimously on Monday to uphold a ban on X after the company refused to obey court orders requiring the removal of profiles accused of spreading disinformation, and for the social network to name a local legal representative.

The Kantar research suggests marketers’ trust in ads on X continues to decrease, from 22% in 2022 to 12% this year. Only 4% of marketers think ads on X provide brand safety.

Last month, X moved to sue a global advertising alliance and several major companies, including Unilever, Mars and CVS Health, accusing them of unlawfully conspiring to shun the social network and intentionally causing it to lose revenue.

“We tried peace for 2 years, now it is war,” Musk tweeted at the time.

Last year, Musk delivered a profanity-laced message to advertisers pulling money from X during an on-stage interview at an event in New York.

An X spokesperson said: “Advertisers know that X now offers stronger brand safety, performance and analytics capabilities than ever before, while seeing all-time-high levels of usage.

“Our brand safety rate is on average 99% as validated by DoubleVerify and Integral Ads Science, which is reflected by the fact that the majority of advertisers are increasing their investment in X, as shown by Kantar’s data.”