Facebook turned in another massive quarter — reporting a quarterly record $21.08 billion in revenue for the fourth quarter of 2019, and announcing that its core app now reaches 2.5 billion users each month.

Still, while it Facebook beat Wall Street expectations on revenue (vs. analyst forecasts of $20.89 billion) and earnings per share of $2.56 (vs. $2.53 estimates), the stock dropped more than 6% in after-hours trading after closing Thursday at an all-time high of $223.23 per share.

Investors were likely worried that the company’s profitability growth rate is slowing down. Net income for Q4 was $7.35 billion. That’s up 7% year-over-year, slower than the social giant’s top-line growth of 25% in the quarter, as Facebook’s operating costs grew 34% to $12.2 billion. (Net income grew 19% in the third quarter of 2019.) Facebook’s operating margin in Q4 was 42% (versus 46% a year prior) but that was up compared with 22%, 27% and 41% in the first three quarters of 2019, respectively.

Facebook also announced it was increasing the size of its share-repurchase program by $10 billion, after previously authorizing repurchases of up to $24 billion of its Class A common stock since 2017.

“We had a good quarter and a strong end to the year as our community and business continue to grow,” Mark Zuckerberg, Facebook founder and CEO, said in a statement. “We remain focused on building services that help people stay connected to those they care about.”

Zuckerberg, on Facebook’s earnings call, reiterated his call for clearer government regulations of internet companies. His company remains in the spotlight over ongoing controversies like Facebook’s refusal to fact-check political ads. Alluding to that, Zuckerberg said his goal for 2020 is for the company is “not to be liked, but to be understood,” saying Facebook will increasingly articulate its positions even if they’re not popular.

The CEO also addressed Facebook’s work to prepare for attempts to influence the 2020 U.S. presidential election, saying, “I do feel confident about where we are… This really is a top priority for us.”

“In 2016, we were behind where we needed to be,” he said, referring to the election that year in which Facebook was one of the platforms Russian operatives used to spread misinformation. “The good news is that since then, this is not like this is the first presidential election we’ve had to defend the integrity of.”

Zuckerberg also talked about Facebook Watch, which he said continues to grow as a dedicated place for users to watch longer-form video: “Think about the content acquisition we do there along the lines of marketing or bringing people into the service.” Facebook recently axed two high-profile original dramas as it continues to greenlight more reality fare like its renewal of Jada Pinkett Smith’s “Red Table Talk.”

Facebook’s monthly active user count stood at 2.50 billion at the end of 2019, a 8% year-over-year increase and up 2% sequentially. Daily active users were 1.66 billion on average for December 2019 (up 9% on an annual basis and a 2% increase quarter-over-quarter).

The company’s total measure of users across Facebook, Instagram, Messenger, and/or WhatsApp — which it calls family monthly active people (MAP) — was 2.89 billion as of the end of 2019, an increase of 9% year-over-year.

Facebook employs more than 1,000 engineers working on data privacy, and this week the company kicked off a program to alert nearly 2 billion users to review their privacy settings, Zuckerberg noted on the earnings call.

On the privacy front, Facebook disclosed that it reached a $550 million settlement this month in connection with a class-action lawsuit alleging the company violated the Illinois Biometric Information Privacy Act by using facial recognition software in its photo-tagging service. That also contributed to Facebook’s higher expenses in Q4.

Going forward, Facebook expects to see a more significant revenue slowdown from privacy-related regulations like Europe’s GDPR and the California Consumer Privacy Act, as well as changes by Apple and Google in their browsers to block third-party tracking and by Facebook itself allowing users to limit data collection. “Each of these factors limits our ability to target and measure the effectiveness of ads on our platform, and that can negatively impact our advertising revenue growth,” said CFO Dave Wehner.

For the first quarter of 2020, Facebook expects year-over-year total reported revenue growth rate to “decelerate by a low to mid-single digit percentage point” versus the Q4 growth rate, he said. “While we have experienced some modest impact from these headwinds to-date, the majority of the impact lies in front of us,” Wehner said.

The company continues to invest in VR and augmented reality, which Zuckerberg called “the holy grail of social experiences.” He said that on Christmas Day 2019, people bought almost $5 million of content on the Oculus Store. “That’s kind of an outlier day, but this is still real volume by any measure,” he said.

Facebook’s non-advertising revenue for Q4 was $346 million, up 26%, which the company said was driven by sales of the Oculus Quest VR headset.

Facebook had 44,942 employees as of Dec. 31, 2019, up 26% from the year prior.