Antitrust enforcers in the US have dug out a jurisdiction for possible investigations into Google, Amazon, Apple, and Facebook.

According to the Financial Times’ sources, this may have cost big tech $133 billion in market value on Monday.

These investigations into big tech will take place thanks to an agreement between the Department of Justice (DoJ) and the Federal Trade Commission (FTC). The four tech giants (Google, Amazon, Apple, and Facebook) will be investigated, but it is currently unclear how far the investigations will go.

The DoJ and FTC are both responsible for antitrust investigations in the US, and they mostly agree on jurisdictions before they launch an investigation. The conclusion the two bodies reached was that the DoJ will be looking into Google and Apple, while the FTC will be looking into Facebook and Amazon, according to the Financial Times’ same sources. While antitrust investigations can often take years to bear fruit, it is possible that an official investigation will be launched in this case. It is quite rare for both the DoJ and the FTC to clarify the jurisdictions in a case without launching an investigation.

Facebook, Google and Amazon initially declined to comment, while Apple initially did not respond to a request for comments. All of these companies have been dragged down in the markets over this breaking news.