There's a widely held belief that regulatory programs rarely achieve what they're intended to achieve. One notable exception has been the DOJ's 2001 Merger Review Process Initiative (MRPI). Designed to reduce the time and cost of merger investigations, the program has done just that by helping the DOJ identify critical competition issues in proposed mergers more quickly and cutting down the agency's requests for additional information.

But requests for additional information–known as “second requests”–still come. And when they do, they are increasingly slowing down the deal process.

The main reason for the slowdown is that courts are relying ever more heavily on the likely competitive effects of transactions and less on market-share presumptions. As a result, the DOJ has had to step up both the quality and the quantity of the information it requests from parties to a merger or acquisition.