Instagram hits 400 million user mark by Kia Kokalitcheva @FortuneMagazine September 22, 2015, 6:53 PM EDT E-mail Tweet Facebook Linkedin Share icons Instagram, the photo-sharing app Facebook bought for a modest $1 billion in 2012, now has more than 400 million users, the company said on Tuesday. Just nine months ago, it had only 300 million. The photo-sharing service added that it is now truly global: more than 75% of its users today are based outside the U.S., and more than half of the last 100 million to sign up are in Europe and Asia. Instagram-owner Facebook FB hasn’t struggled in the area of user growth for quite some time. The parent company now has 1.49 billion monthly active users. WhatsApp, a mobile messaging app it acquired in 2014 for roughly $19 billion, recently revealed it has grown to 900 million users. Though Facebook is simply updating investors on Instagram’s latest user count, the social network is likely hoping to send the subtle message to investors that it’s working hard at turning Instagram into a cash cow. Instagram has gotten several new features and updates in recent months, including improvements to its private messaging to compete with Twitter’s, and that’s paying off in the form of new users. It has also expanded its advertising platform, something analysts eagerly asked about in July when Facebook reported its latest quarterly earnings figures. Their inquiries thinly veiled worries that the company could lose its cool factor if it lets Instagram slip.