According to data recently released by Westlaw, private antitrust lawsuits are in the decline in the United States. The data indicates that in 2009, the Department of Justice (DOJ) consolidated 12 multi-district lawsuits in U.S district courts, while last year it only consolidated four.

Some plaintiffs lawyers suggest that the decrease can be attributed to the DOJ being less aggressive in launching new probes against companies that potentially violate antitrust laws. The thinking is, when the DOJ launches an investigation into antitrust violations against a company, plaintiffs begin filing suits against that company claiming they were harmed as a result of the alleged antitrust violation.

The DOJ denies it’s being less vigorous in its effort against potential antitrust violators. Read more about Westlaw’s data on private antitrust lawsuits declining from Reuters.