The US Federal Trade Commission (FTC) has ordered five major tech companies to hand over detailed information on hundreds of acquisitions made over the past decade, it announced on Tuesday.

As part of its continued antitrust investigations, the agency, which enforces consumer protection laws, has required Google, Microsoft, Amazon, Apple and Facebook to provide documents and other information on the purpose and scope of their takeovers of smaller companies from 2010 to 2019.

Large acquisitions, such as Facebook’s purchase of Instagram in 2012 or Amazon’s acquisition of Whole Foods, must be approved by the FTC in advance. But the FTC said the focus on deals small enough not to have been legally required to be named in previous filings will help the agency understand “whether large tech companies are making potentially anticompetitive acquisitions of nascent or potential competitors”.

Apple’s chief executive, Tim Cook, has said the company buys smaller companies on an average of every two to three weeks.

Joe Simons, the FTC chairman, said in a statement that the initiative “will enable the Commission to take a closer look at acquisitions in this important sector, and also to evaluate whether the federal agencies are getting adequate notice of transactions that might harm competition”.

The intensifying scrutiny comes amid calls from some lawmakers to overhaul the FTC entirely, saying it is not doing enough to hold big tech accountable. Senator Josh Hawley, of Missouri, introduced a plan on Monday proposing the agency be absorbed into the Department of Justice.

“The FTC isn’t working,” Hawley said in a statement announcing the proposal. “It wastes time in turf wars with the DOJ, nobody is accountable for decisions, and it lacks the ‘teeth’ to get after Big Tech’s rampant abuses.”

However, critics of Hawley say the proposal reflects his belief that digital platforms deliberately operate with bias against conservatives, and that changes to the FTC would not offer any meaningful benefits to Americans.

“Justice department also has a poor record fighting against mergers from the digital industry,” said Jeff Chester, the executive director of the Center for Digital Democracy, a not-for-profit consumer protection group. “The last thing Americans need now is to allow the justice department to become the ‘super’ agency addressing the surveillance economy.”

Tuesday’s announcement marks just the latest inquest into big tech. It comes after dozens of states launched antitrust investigations into tech companies in September 2019, focusing on whether Facebook’s dominance in the digital space has unfairly stifled competition and looking at Google’s digital advertising impact.

The FTC said it would consider the information requested when evaluating whether smaller mergers should also be disclosed ahead of time.

Amazon declined to comment on the investigation, while Google, Apple and Facebook did not immediately respond to requests for comment.

A Microsoft spokesperson said: “We look forward to working with the FTC to answer their questions.”