What happened

Shares of Alphabet (GOOG 1.04%) (GOOGL 1.07%) fell 10.1% in September, according to data from S&P Global Market Intelligence. The search giant and tech conglomerate was caught up in the general technology sector sell-off following a blockbuster August. However, Alphabet also had the added headwind of a looming antitrust investigation from the U.S. Justice Department.

A book with the words Antitrust Law on the cover.

Image source: Getty Images.

So what

After a sterling month of August when many of the technology and especially FAANG stocks hit all-time highs, things turned hard in September. Profit-taking, combined perhaps with some apprehension about the upcoming presidential election, led to the sell-off across the technology sector.

Alphabet then garnered additional negative headlines early in the month, after Attorney General William Barr said the Justice Department would be bringing an antitrust case against Alphabet "very soon." According to the New York Times, Barr is overruling other Justice Department employees who think they need more time. It's still unclear what kind of antitrust violations will ultimately be brought; however, scrutiny of Alphabet's near-90% share of search advertising is likely a target.

Now what

While the coming antitrust charges are definitely a concern for Alphabet, it's not necessarily a reason to sell the stock. For one, even if charges are brought, Alphabet will be able to defend itself before a judge. According to the Times, several Justice Department lawyers left the case this summer and disagree with the rushed approach being taken. Other state attorneys general have also voiced skepticism and concerns over the Justice Department's strategy.

Meanwhile, it's possible these concerns are already factored into Alphabet's share price. The company has lagged the other FAANG stocks this year, and when factoring in its cloud business, large pile of cash, and other bets, the stock actually appears quite cheap. After a rough month, Alphabet investors should probably stay the course, pending more information.