X, the social media company formerly known as Twitter, could lose as much as $75 million in advertising revenue by the end of the year as dozens of major brands pause their marketing campaigns after its owner, Elon Musk, endorsed an antisemitic conspiracy theory this month.

Internal documents viewed by The New York Times this week show that the company is in a more difficult position than previously known and that concerns about Mr. Musk and the platform have spread far beyond companies including IBM, Apple and Disney, which paused their advertising campaigns on X last week. The documents list more than 200 ad units of companies from the likes of Airbnb, Amazon, Coca-Cola and Microsoft, many of which have halted or are considering pausing their ads on the social network.

The documents come from X’s sales team and are meant to track the impact of all the advertising lapses this month, including those by companies that have already paused and others that may be at risk of doing so. They list how much ad revenue X employees fear the company could lose through the end of the year if advertisers do not return.

On Friday, X said in a statement that $11 million in revenue was at risk and that the exact figure fluctuated as some advertisers returned to the platform and others increased spending. The company said the numbers viewed by The Times were either outdated or represented an internal exercise to evaluate total risk.

The advertising freezes come during the final three months of the year, which is traditionally the social media company’s strongest quarter as brands run holiday promotions for events such as Black Friday and Cyber Monday. In the last three months of 2021 — the last year the company reported fourth-quarter earnings before Mr. Musk took over — the company recorded $1.57 billion in revenue, of which nearly 90 percent came from advertising.

Since Mr. Musk’s $44 billion acquisition of Twitter last year, some brands have been hesitant to advertise on the platform, concerned with Mr. Musk’s behavior and content moderation decisions, which have led to a rise in incendiary and hateful content. U.S. advertising on the platform is down nearly 60 percent this year, prompting the company to try to woo back advertisers in an effort its chief executive, Linda Yaccarino, is spearheading. X is also running ad campaigns during the holiday period to try to make up for revenue shortfalls.

The documents, however, reveal that has not been going to plan. More than 100 brands are shown as having “fully paused” their ads while dozens of others are listed as “at risk.” Many paused on or after Nov. 15, when Mr. Musk wrote in a post on X that the conspiracy theory that Jewish people supported the immigration of minorities to replace white populations was “the actual truth.”

Leesha Anderson, the vice president of digital marketing and social media at the advertising agency Outcast, said its clients steadily stopped spending on X after Mr. Musk took over and had found alternatives on platforms like LinkedIn and TikTok.

“In today’s dynamic marketplace, brands have a plethora of platform choices at their disposal for precise audience targeting,” she said. “Therefore, it is imperative for the stewards and proprietors of social platforms to exercise deliberate discretion in all aspects, be it their personal beliefs or political stances, as these choices will inevitably undergo public scrutiny.”

The organizations that have paused their ads on X range from political campaigns to fast food chains to tech giants, according to the documents. Airbnb, for example, halted more than $1 million of advertising, while Uber cut back on ads worth more than $800,000, halting campaigns in U.S. and international markets. Both tech companies declined to comment.

Other large brands, including Jack in the Box, Coca-Cola and Netflix, paused some of their campaigns. Netflix’s halted ads were worth nearly $3 million, according to X’s estimates. Jack in the Box, Coca-Cola and Netflix did not respond to requests for comment.

Various subsidiaries of Microsoft have also stopped advertising — leading to a potential loss of more than $4 million in revenue for X’s fourth quarter, based on the documents — as have Amazon’s units for books and music and one subsidiary of Google. The search giant and some other brands that have paused spending, including NBC Universal, have continued to post content on the platform without paying X to ensure it reaches a broad audience.

Google and Microsoft declined to comment. Amazon did not return requests for comment.

On the NBC program “Meet the Press” last Sunday, the Republican presidential candidate Chris Christie called Mr. Musk’s comment part of a recent outpouring of an “outrageous type of hate.”

“Whether it’s Elon Musk, whether it’s professors on our college campuses or students that they are misleading, or whether it’s individuals who are speaking out in an antisemitic way on the streets of our cities,” he said.

Two days before Mr. Christie’s appearance, a super PAC supporting him, called Tell It Like It Is, pulled its advertising from X, according to the documents. A representative for the political fund-raising group did not respond to a request for comment.

In an internal meeting with employees at X this week, Ms. Yaccarino cut a defiant mood. She made no mention of Mr. Musk’s endorsement of the antisemitic post and attributed the company’s problems to a report by the left-wing media watchdog group Media Matters, which showed that ads on X from companies like IBM and Apple appeared next to posts promoting white nationalist and Nazi content.

On Monday, after Mr. Musk called Media Matters “an evil organization,” X sued the group and argued that its report, which was published after Mr. Musk’s statement, “manipulated the algorithms governing the user experience on X to bypass safeguards and create images of X’s largest advertisers’ paid posts adjacent to racist, incendiary content.” Ms. Yaccarino has blamed the Media Matters’ report for X’s declining ad sales.

“Kowtowing to external criticism or pressures is simply not how X will ever operate,” she wrote in an email to X employees on Wednesday that was seen by The Times. “The people at X are free speech defenders. We stand in solidarity with those who believe in this fundamental right and the critical checks and balances of a thriving democracy.”

Earlier this week, Mr. Musk spent time celebrating companies that have continued to advertise on X, including the National Football League. Using a heart emoji, X’s billionaire owner said he loved the N.F.L. (The New York Times largely stopped marketing on the platform in early 2023, though the company’s sports publication, The Athletic, has continued to purchase ads, according to a spokesman.)

Mr. Musk also noted that the company would donate “all revenue from advertising & subscriptions associated with the war in Gaza to hospitals in Israel and the Red Cross/Crescent in Gaza.” The funding will include revenue from ads bought by charity groups, news organizations and other groups that advertised content related to the conflict.

Following her boss, Ms. Yaccarino added to Mr. Musk’s original post with a plea.

“Lean in and help,” she wrote on X.

Tiffany Hsu contributed reporting.