Facebook, which has been reeling from drops in the stock market, is now facing another hurdle in its growth with a high number of illegitimate accounts. In a quarterly filing with the US Securities and Exchange Commission, the social network revealed that the number of Facebook users rose to 955 million at the end of July. However, 8.7% of the increase is actually dubious accounts.

Duplicate accounts, wherein a certain member uses and maintains more than one profile, account for 4.8%. Some 2.4%, on the other hand, come from “user-misclassified” accounts made for businesses, groups, or “non-human entities” such as pets. There are also 1.5% “undesirable” accounts, which are used to send spam messages and other illegal and malicious activities.

Facebook said that a higher number of illegitimate accounts was recorded in developing countries such as Indonesia and Turkey than in the United States, Australia and other developed markets. The company added that it is looking into the matter and will take the necessary steps to address the issue. “We are continually seeking to improve our ability to identify duplicate or false accounts and estimate the total number of such accounts, and such estimates may be affected by improvements or changes in our methodology,” Facebook said in the filing.

The emergence of illegitimate accounts is a blow to the company, which has been criticized for its alleged weak business model. Facebook heavily relies on advertisements to generate revenues and if the number of such dodgy accounts continue to grow, it will be bad for the social giant.

Earlier, digital distribution company Limited Press complained that 80% of recorded clicks on its advertisements on Facebook were actually made by fake users. It said that bots are “driving up” its advertising costs. It called on the social network to look into the problem, as it affects its business and advertising strategy.

Facebook is the leading social network today. Given this, many companies invest in advertising via the social giant. But analysts believe that companies want to ensure that the “likes” they will receive come from real Facebook users. Otherwise, they may pull out their advertising investment from the social network.