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Facebook stock fell as much as 8 percent as the market opened Thursday after it reported fourth-quarter earnings Wednesday evening.

The drop erased more than $50 billion from the social media giant’s market value, which now sits below $600 billion.

The drop comes after Facebook reported a 51 percent rise in expenses compared to its total in 2018. The expenses were largely related to the company’s privacy and security improvements. That coincides with a drop in the company’s operating margin, which fell from 45 percent in 2018 to 34 percent in 2019.

In addition to the increased expenses, Facebook also warned of advertising headwinds related to privacy and regulatory changes on the horizon, leading to slowing growth in the U.S. Facebook said privacy improvements on Apple’s iPhones and Google’s Android software could hurt its ability to target advertising. In a note to investors Thursday, Pivotal Research Group reduced its rating from buy to hold on those advertising concerns.

Those privacy-related expenses and advertising headwinds are expected to continue throughout 2020. Facebook CEO Mark Zuckerberg said on the company’s earnings call Wednesday that privacy will be a focus for the company this year.

“It’s going to take time, but over the next decade I want us to build a reputation on privacy that’s as strong as our reputation already building good, stable services,” Zuckerberg said.

This story is developing. Please check back for updates.