Over 15 percent of Republican presidential candidate Mitt Romney's Twitter followers may be fake.

According to security firm Barracuda Labs, Romney may have bought followers, with 116 000 accounts following him in just 24 hours last month.

Roughly a quarter of the accounts are four days old and just under a quarter have never tweeted. Additionally, ten percent of the followers have already been suspended by Twitter.

"Based on the above distinguishable features, we believe most of these recent followers of Romney are not from a general Twitter population but most likely from a paid Twitter follower service," Barracuda Labs said.

According to the study, users can buy up to 1000 followers for an average price of $18, while 2000 retweets can be had for $5.

Of course, fake accounts are against Twitter's terms of service.