According to a Tuesday report from The Outline, news outlets such as Forbes, Fast Company, and the Huffington Post have taken payment from companies in exchange for positive coverage.

Outline reporter Jon Christian claimed that brands have constructed elaborate payment schemes in exchange for positive coverage in popular news outlets such as Mashable, Business Insider, and Entrepreneur.

People involved with the payoffs are extremely reluctant to discuss them, but four contributing writers to prominent publications including Mashable, Inc, Business Insider, and Entrepreneur told me they have personally accepted payments in exchange for weaving promotional references to brands into their work on those sites. Two of the writers acknowledged they have taken part in the scheme for years, on behalf of many brands. Mario Ruiz, a spokesperson for Business Insider, said in an email that “Business Insider has a strict policy that prohibits any of our writers, whether full-time staffers or contributors, from accepting payment of any kind in exchange for coverage.”

According to the report, outlets such as the Huffington Post and Forbes are susceptible to content in which authors have received payment because both sites maintain a roster of contributors who are free to publish material on their own.

“Many high-volume sites, including the Huffington Post, Entrepreneur, and Forbes, maintain networks of unpaid contributors who publish large amounts of material,” Christian wrote. “Forbes, for instance, marks articles by contributors with a small disclaimer, but the Columbia Journalism Review has pointed out that those dubiously sourced articles are often cited as though they were normal stories written by Forbes staff. In reality, the editorial process that leads to those articles being published is opaque.”

An unnamed Huffington Post contributor told Christian that he has included sponsored references in his articles for many years. According to the source, the amount for each reference can be as little as $50 to $175. The anonymous writer claimed that sometimes the firms provide him with a pre-written article that he simply publishes under his byline. Other times, he drops a mention of their product or service into his own writing.

In a statement provided for Christian’s article, the Huffington Post condemned any use of their platform to publish sponsored content. “Using the HuffPost Contributors Network to self-publish paid content violates our terms of use. Anyone we discover to be engaging in such abuse has their post removed from the site and is banned from future publication,” the statement read.

Reporters from various news outlets told Christian that they receive offers from advertising agencies seeking positive coverage. An agency called ArticleHub claims that they will pay $5,000 for a brand mention in the New York Times, $4,500 in TechCrunch, and $3,000 in Business Insider. ArticleHub says they will pay $4,000 for a feature story in Forbes.