FACTBOX-Big Tech's market dominance spurs numerous U.S. antitrust probes

Oct 20 (Reuters) - The U.S. Justice Department is expected to file a lawsuit against Alphabet Inc's Google on Tuesday in what could be just the first in a series of legal salvos against high-profile tech companies.

It has been known for more than a year that Amazon.com Inc , Apple Inc and Facebook Inc also face an array of antitrust probes on both the federal and state levels.

While Democrats may be viewed as tougher on antitrust regulation, traditional Republican concerns about regulatory overreach appear to be outweighed by anger on the political right over claims that Big Tech tries to stifle conservative voices.

The following are other inquiries now under way.

Justice Department on Apple: This probe, revealed in June 2019, appears to focus on Apple's app store. Some app developers have accused Apple of introducing new products very similar to pre-existing apps created by other developers and sold in the Apple Store, and then trying to banish the earlier apps from the store because they compete with Apple's new product. Apple says it seeks to have only the highest-quality apps in the app store.

Justice Department on Facebook and Amazon: In July 2019, the Justice Department said it was expanding its Big Tech probes to include "search, social media, and some retail services online" - an apparent reference to Facebook and Amazon.

Federal Trade Commission on Facebook: FTC officials probing Facebook have asked about past acquisitions, such as those of Instagram and WhatsApp, and how Facebook treats app developers on its platform. The FTC told Facebook in June 2019 it was probing whether the company has engaged in unlawful monopolistic practices.

Federal Trade Commission on Amazon: In its investigation of Amazon, the FTC is likely looking at the inherent conflict of interest of Amazon competing with small sellers on its marketplace platform, including allegations that it used information from sellers on its platform to decide what products it would introduce.

State attorneys general probe Google: A group of state attorneys general led by Texas is expected to file a lawsuit focused on digital advertising, perhaps as early as November. Meanwhile, a group led by Colorado is contemplating a more expansive lawsuit against Google that may also include concerns about its Android business.

State attorneys general probe Facebook: New York Attorney General Letitia James, who leads the state attorneys general probing Facebook, has said the investigation would examine whether the company's actions endangered consumer data, reduced consumer choice or increased the price of advertising. (Reporting by Diane Bartz in Washington Editing by Matthew Lewis)