Celebrity-backed brands and endorsements are everywhere. But outside these formal, contract-bound relationships, in the jungle of everyday social media—where Kylie Jenner can hack $1.3 billion off Snapchat’s market value with a single tweet—who represents the biggest threat to brands? Which celebrities could, wittingly or not, negatively impact the public’s relationship with a brand?

To find out, we analyzed dozens of the world's biggest celebrities, measuring their familiarity, trust, influence and social reach, in order to establish the top 24 most powerful figures. In determining our “Smack Score” for each celebrity—the person’s ability to negatively influence public opinion of a brand—we considered six factors. Measures of familiarity, trust and influence were established in a survey of 2,000 Americans, two other factors were existing social metrics, and one factor, “Instagram Quotient,” was calculated using a trend line analysis of what each celebrity would be paid for sponsored posts based on industry precedents. Let's take a deeper look at which star packs the hardest punch. 

Celebrity Influence on Brands

Methodology

To understand the influence the world's top stars have on our opinions on brands, we looked at several factors. We determined the first three categories — familiarity, trust and influence — by surveying 2,000 people. Additionally, we examined each celebrity's social following, pulling data from Twitter and Instagram. We established each star's Instagram quotient by analyzing trendline data pulled from industry benchmarks for paid social posts. This allowed us to estimate how much money each celebrity has the potential to earn with one post. 

Ranking

While a variety of stars on our list had impressive Instagram quotients and social followers, what really knocked Gigi Hadid and Steph Curry down to the bottom of our ranking was familiarity. Although she's not as commonly known, Gigi Hadid still represents the most number of brands out of all the other celebrities, showing that marketers might not be as worried about the concept of familiarity as we once thought. Low familiarity scores also affected Chrissy Teigen and Cristiano Ronaldo, who rounded out the bottom four. 

While the industries of stars representing spots 11-20 vary between athletes, comedians and reality stars, 70% of them are male. Tom Hanks and Leonardo DiCaprio pull ahead in this group with 10 out of 10 in familiarity, but low earning Instagram quotients, especially in comparison to Kylie Jenner and Kim Kardashian, who can earn up to $415,000 and $427,000 respectively per post. 

Oprah brings us into the top 10 with an unsurprising 10 out of 10 in familiarity and 5th place overall in terms of trust. What's a little more unexpected is Rihanna and Katy Perry's surpassing Oprah with total smack scores of 83 and 83.7 respectively.

Former first lady Michelle Obama comes in 7th with an 83.9 total smack score, followed by Beyoncé, Taylor Swift and Selena Gomez. Third overall is former President Barack Obama. Ellen DeGeneres comes in at 2nd and Dwayne Johnson tops our list with a smack score of 94.9.

Additional Findings

While they didn't land the coveted number one spot, Ellen DeGeneres and Tom Hanks tied for most trusted stars. Gigi Hadid and Kylie Jenner had the opposite luck and are the least trusted on our list. Barack Obama reigns supreme with the highest score for influence. It's important to note that while he'd be the ideal spokesperson, the former president has never endorsed any company, nor will he in the future. Overall, over half of the stars on our rankings are women, and 10 out of 24 are people of color.