The Facebook investigations are part of a larger landscape of probes of big tech firms over anti-trust violations.
A New York-led probe into allegations that Facebook put consumer data at risk and pushed up advertising rates has expanded to include attorneys general from 47 U.S. states and territories, New York Attorney General Letitia James said in a statement Tuesday.
The investigation of Facebook announced in September had included Colorado, Florida, Iowa, Nebraska, North Carolina, Ohio, Tennessee and the District of Columbia. It now includes most U.S. states as well as the U.S. territory of Guam.
The statement provided a list of states involved in the probe and added that other states "cannot confirm their participation in pending investigations." California, the largest state by population, was not on the list. The Facebook investigations are part of a larger landscape of probes of big tech firms over anti-trust violations.
Some states, particularly New York and Nebraska, have raised concerns that Facebook and other big tech companies engage in anti-competitive practices, expose consumer data to potential data theft and push up advertising prices.
Facebook justified its practices saying that its users had multiple choices for the services that the company provides.
Facebook also faces probes by the U.S. Justice Department and the Federal Trade Commission, as well as the House of Representatives Judiciary Committee.
Medias reported in June that the Justice Department and FTC had divided responsibility for the companies being investigated, with the Justice Department taking on Alphabet Inc's Google and Apple while the FTC looked into Facebook and Amazon.
The Justice Department later said it was opening a probe of online platforms, which would include Facebook.