Facebook reported quarterly earnings and revenue that beat analyst expectations on Wednesday, but CFO David Wehner said ad revenue growth rates would slow meaningfully in 2017.

Ad load — the ratio of ads to personal posts — has been an important factor in delivering strong growth in advertising revenue over the past two years but will taper off in the second half off 2017, Wehner told analysts on the company's earnings conference call. Ad revenue growth has averaged 50 percent over the past two years, he said.

Facebook is getting close to maxing out the number of ads it can cram into news feeds without damaging user experience. As a result, it won't be able to increase so-called ad load at the same rate next year.



Facebook will continue to invest in growing its user base and the amount of time those users spend on Facebook, Wehner said. Those are two other factors fueling ad revenue growth at the social media giant.



