Facebook reported third-quarter profit and sales that topped Wall Street expectations, but its shares fell after it said on a conference call that 2018 expenses would rise 45 percent to 60 percent, or faster than expected sales.

After trading as high as $185 a share soon after the results were released, the stock fell as much as 2 percent, to near $179, after the company issued its initial 2018 expense forecast.

Facebook shares have risen more than 50 percent this year.

Here's the key data:

EPS: $1.59 per share, more than the $1.28 a share expected.

Revenue: $10.3 billion, up 47 percent and more than $9.84 billion expected

MAUs: 2.07 billion versus 2.06 billion expected

Facebook CEO Mark Zuckerberg warned that protecting the site from those wanting to spread fake news and hate speech will drive costs higher.

"We're serious about preventing abuse on our platforms. We're investing so much in security that it will impact our profitability," Zuckerberg said.

On a conference call to discuss the results, he added that protecting Facebook's community is "more important" than boosting profit.

The company said yesterday it would double to 20,000 the number of workers dedicated to keeping fake news and hate speech off its sites by the end of next year.

CFO David Wehner said on the same call that 2018 operating expenses will rise significantly as the company pays more for security and original content.

Capital expenditures will double next year, Wehner said.