The first misunderstanding is about Facebook itself and the competitive dynamics in which we operate. We are a large company made up of many smaller pieces. All of our products and services fight for customers. Each one has at least three or four competitors with hundreds of millions, if not billions, of users. In photo and video-sharing, we compete against services like YouTube, Snapchat, Twitter, Pinterest and TikTok, an emerging competitor.

In messaging, we’re not even the leader in the top three markets — China, Japan and, by our estimate, the United States — where we compete with Apple’s iMessage, WeChat, Line and Microsoft’s Skype. Globally, the context in which social media must be understood, China alone has several large social media companies, including powerhouses like Tencent and Sina. It will seem perverse to people in Europe, and certainly in China, to see American policymakers talking about dismantling one of America’s biggest global players.

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In this competitive environment, it is hard to sustain the claim that Facebook is a monopoly. Almost all of our revenue comes from digital advertising, and most estimates say Facebook’s share is about 20 percent of the United States online ad market, which means 80 percent of all digital ads happen off our platforms.

The second misunderstanding is of antitrust law. These laws, developed in the 1800s, are not meant to punish a company because people disagree with its management. Their main purpose is to protect consumers by ensuring they have access to low-cost, high-quality products and services. And especially in the case of technology, rapid innovation. That is exactly where Facebook puts its attention: building the best products, free for consumers, and funded by advertisers.

What antitrust law isn’t about is size alone. In Facebook’s case, our size has not only brought innovation, it has also allowed us to make a huge investment in protecting the safety and security of our services.

Over the past two years we’ve focused heavily on blocking foreign adversaries from trying to influence democratic elections by using our platforms. We’ve done the same to protect against terrorism and hate speech and to better safeguard people’s data. And the resources that we will spend on security and safety this year alone will be more than our overall revenues at the time of our initial public offering in 2012. That would be pretty much impossible for a smaller company.