So far, 2019 has been a year of growth for the nation's largest tech companies while U.S. lawmakers and regulators question how big is too big.

Four of the five FAANG stocks — Facebook, Amazon, Apple and Netflix— have grown their market value at least 25% over the past six months. Microsoft, currently the largest public tech company in the U.S. with a market cap topping $1 trillion, has also grown its shares more than 31% since the beginning of 2019.

Only Google parent company Alphabet saw more modest growth of 3.6% since the beginning of the year.

Of the group, Facebook saw the biggest rally in its stock price, jumping more than 47% since the beginning of the year to reach a market cap of $550.9 billion. Netflix shares jumped more than 37% while Apple and Amazon both saw their stock prices rise more than 25%.

During that time, lawmakers and regulators in the U.S. and abroad have lobbed criticism at Big Tech. Skeptics, which include presidential contenders like Massachusetts Sen. Elizabeth Warren, say the tech firms have grown too large and abuse what they call dominant market positions.

While the refrain "break up Big Tech" had been floated around even before Warren's policy proposal, investors seemed to see it as a more concrete possibility earlier this month. Shares of Facebook, Alphabet, Amazon and Apple tumbled following reports that top U.S. antitrust regulators were divvying up oversight responsibility over the companies.

But even over the past month, all of those companies except Alphabet have grown their stock price, showing investors are still largely confident in the tech industry's staying power. Facebook's stock actually went up after hours in April when it said it expected a one time charge of up to $5 billion in connection with the Federal Trade Commission's investigation into whether it violated a 2011 consent decree.

Other major tech stocks are also having a great start to the year.

Snap, which is much smaller than the other tech giants at a $19.2 billion market cap, has seen explosive growth this year. The stock is up nearly 160% in 2019. Earlier this month, BTIG analysts wrote that the company's comeback has been flying under investors' radar as it has introduced new products and monetization opportunities.

Tesla, on the other hand, has had a more turbulent start to the year as it has entered cost-cutting mode. The company, which has a market cap of $39.5 billion, has seen its shares fall more than 32% in 2019.

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