Kim Kardashian and her siblings have been accused of deceptive advertising by posting over 100 product placements on Instagram without acknowledging their paid relationships with the companies and products promoted.

Truth in Advertising called the family out in a letter and gave the clan a week to remove the posts before it contacts the FTC, which could open an official investigation of the matter.

The watchdog group known as TINA noted that Kylie Jenner had the largest number of posts with undisclosed sponsorship content, while sister Kim came in second. Kylie's deal with the Puma brand was the most problematic, with 14 posts about the company on her Instagram account, while Kim, Khloe and Kourtney had the same total number of posts about Fit Tea products on their accounts without disclosing their paid relationships with the product.

While many fans are already aware of the Kardashians' sponsorship deals (Kylie's Puma sponsorship was the subject of a recent episode of their E! TV show), the family is still required by the FTC to disclose its paid relationships by using simple words or phrases such as "paid ad," "sponsored" and "promotion" in their posts.

"When it comes to sponsored social media posts, the law is clear — unless it's self-evident that an Instagram post is an advertisement, a clear and prominent disclosure is required so that consumers understand that what they are viewing is an ad," said TINA.org Executive Director Bonnie Patten.

It appears that the threat issued by the company to contact the FTC may actually be having some effect. After TINA sent the letter to the sisters and published its findings in a blog post, Kim began a newly published Instagram post beginning with the hashtag #ad. The post is for the product Sugar Bear Hair, which is promoted on several of the sister's Instagram pages.

Kim also amended a June post for the same product with the #ad hashtag, and sisters Kylie and Khloe then did the same for at least one of each of their prior posts for Sugar Bear Hair. While Sugar Bear Hair was one of the many products and companies mentioned in TINA's list of offending posts, it is currently the only one in which the hashtag has been added by any of the sisters. This indicates that it may in fact be the company itself and not the Kardashians who insisted on the changes.

The makers of Sugar Bear Hair may be concerned about a potential FTC crackdown on undisclosed advertising posts. After Lord & Taylor paid fashion influencers to post pictures of a dress on Instagram in March, the FTC took action against the department store chain. With the company and not the paid posters having been the target, the Kardashians may still be willing to flout the rules as long as their sponsors are willing to take the heat of any potential consequences.

How the Kardashians handle their subsequent Instagram posts for sponsors should indicate whether the TINA exposé has had any direct effect on their behavior.