Facebook says 8.7 percent of its monthly active user total might violate terms of service and be either duplicate, miscategorized or “undesirable” accounts meant for spamming, according to a filing with the Securities and Exchange Commission.

In its quarterly report, Facebook provided updated numbers and new details about illegitimate accounts, which could represent about 83 million users. The company estimates 4.8 percent of its 955 million monthly active users are duplicate accounts. For instance, a user may use one account for connecting with work acquaintances and another for family and close friends.

Facebook says 2.4 percent of accounts are likely miscategorized accounts where users have created personal profiles for a business, organization or pet. These entities should be represented on Facebook with pages, not profiles, according to the social network’s terms of service.

Facebook also estimates that 1.5 percent of monthly active users are “undesirable accounts,” which are false accounts that are created for spamming or other purposes that violate terms. Earlier this week, a music startup claimed that 80 percent of clicks on its Facebook ad campaign came from bots. Facebook says it is investigating the claims.

According to Facebook’s quarterly report, the percentage of accounts that are duplicate or false is significantly lower in developed markets such as the United States or Australia but higher in developing markets such as Indonesia and Turkey. The company says it creates these estimates based on an internal review of a limited sample of accounts. Reviewers identify names that appear to be fake and other behavior that appears inauthentic.

In March, Facebook estimated 5 to 6 percent of its 845 million monthly active users could be false or duplicate accounts. At that time, the company did not offer estimates about what percentage of these accounts were duplicate, miscategorized or otherwise undesirable.