In June 2023, YouTube decided to stop fighting the most persistent strain of election misinformation in the United States: the falsehood that President-elect Joe Biden stole the 2020 election from then-President Donald Trump.

Within months, the largest video platform became a home for election conspiracy theories, half-truths and lies. They in turn became a source of revenue for YouTube, which announced growing quarterly ad sales on Oct. 29.

During four tumultuous months of this year’s presidential campaign, researchers from Media Matters for America, a group that monitors information from conservative sources, examined the consequences of YouTube’s about-face.

While Media Matters is a progressive organization that regularly criticizes conservatives, reporters and academics frequently cite it as a source on YouTube misinformation because it devotes significant resources to tracking the vast platform.

The New York Times independently verified the research, examining all of the videos identified by Media Matters and determining whether YouTube placed ads or fact-check labels on them. From May through August, Media Matters tracked 30 of the most popular YouTube channels they identified as persistently spreading election misinformation.

The 30 conservative channels posted 286 videos containing election misinformation, which racked up more than 47 million views. YouTube, which is owned by Google, generated revenue from more than a third of those videos by placing ads before or during them, researchers found. Some commentators also made money from those videos and other monetized features available to members of the YouTube Partner Program.

Commentators included former elected officials, such as Rudy Giuliani, who disputed the results of the 2020 race, media figures like Tucker Carlson, who said the last presidential election was stolen, and pundits like Ben Shapiro, who said Democrats “rigged” voting rules in 2020.

Giuliani, the former New York mayor, posted more false electoral claims to YouTube than any other major commentator in the research group, the analysis concluded. He said in May, for example, that if he did not rehash the 2020 election, the 2024 election would be stolen.

Carlson and Shapiro did not directly respond to a series of questions but attacked reporting from The Times. Giuliani said in a post on the social platform X that he was “proud to be included with Ben and Tucker — two GREAT Patriots!”

A YouTube spokesperson said that the company reviewed eight videos, identified by the Times, and that those did not violate its community guidelines.

“Most” of the 30 tracked channels are “ineligible for advertising,” and some had previously violated YouTube’s content policies, the spokesperson said. “This report demonstrates our consistent approach to enforcing our policies.” YouTube said it removes videos that mislead voters on how to vote, encourage election interference or make violent threats.