Here is a rundown of Cheddar News' top market stories of the day. 
The Biden administration on Tuesday marked another milestone in its efforts to challenge Big Tech's monopoly practices. The U.S. Department of Justice filed an antitrust lawsuit against Google parent Alphabet, alleging that it "used anticompetitive, exclusionary, and unlawful conduct" to reduce competition in the digital advertising technology space. The DOJ said the company's dominance over the last 15 years has harmed online publishers, advertisers, and consumers who heavily rely on digital ad tech. The lawsuit comes three years after the federal government filed a civil suit aimed at Google's search and search advertising business. 
Elon Musk defended himself in federal court on Tuesday in a trial over tweets. The class-action lawsuit alleges that Musk misled Tesla shareholders when he tweeted about the possibility of taking the company private. The billionaire executive spent roughly three hours on the stand and exchanged heated remarks with the prosecutor before being excused by U.S. District Judge Edward Chen. It's likely that it will be Musk's last appearance on the witness stand for this trial. 
Rupert Murdoch has squashed plans to combine two parts of his empire, the Fox Corporation and News Corp, saying the merger was “not optimal" for shareholders. Murdoch reportedly proposed the merger back in October and then established independent committees to evaluate its pros and cons. The merger would have reunited companies that split a decade ago, such as Fox News, TMZ, and the Wall Street Journal, under one corporate umbrella.