Facebook Inc.'s growth is slowing due in part to a decline in users of the social network in the U.S., according to a new study.
Facebook lost nearly 6 million users in the U.S. last month, falling from 155.2 million at the start of May to 149.4 million at the end of the month, said Eric Eldon, an editor at Inside Facebook, a research and marketing group that conducted the study. It was the first monthly decline in a year, he said.
"Most of the new users continue to come from countries that are relatively late in adopting Facebook, as has been the trend for the past year," Eldon said, adding that "Facebook is still growing towards 700 million users, having reached 687 million monthly actives by the start of June."
The social media giant gained 11.8 million new users worldwide in May, down from 13.9 million new accounts in April, Eldon said. Previous to those two months, Facebook had grown by an average of 20 million new users a month for the last 12 months, he said.
"While there have been a few months that have registered lower growth numbers, they have not been back to back," Eldon said.
The study's data come by way of estimations from Inside Facebook, which runs the Inside Facebook website, with studies and news items directed at developers, journalists and marketers.
Facebook doesn't publicly release its monthly traffic numbers. But the Palo Alto company said in a statement that it was happy with its traffic growth and that more than 50% of users log in every day.
"From time to time, we see stories about Facebook losing users in some regions," Facebook said. "Some of these reports use data extracted from our advertising tool, which provides broad estimates on the reach of Facebook ads and isn't designed to be a source for tracking the overall growth of Facebook."
According to Inside Facebook, the United Kingdom, Norway and Russia each posted losses of more than 100,000 in May. "If these countries — most of whom had adopted Facebook many years ago — had not lost users, and instead posted even small gains, Facebook would have had a much more typical month," Eldon said.
To offset losses, Facebook has relied on emerging markets with large populations such as Brazil, India, Indonesia and Mexico, the Inside Facebook study said.