It has long been recognized that patent pools can create licensing efficiencies by establishing “onestop shops” for patents owned by multiple rights owners. There is also broad consensus that patentee collaboration in patent pools can raise antitrust risks. Over the years, business review letters from the Department of Justice Antitrust Division (DOJ) and other agency guidance has established a blueprint for antitrust safeguards that have been implemented in numerous patent pools. There has been a catch, however: on their face, all relevant DOJ business review letters applied only to pools of standard essential patents (SEPs). Whether and how the principles set forth in these letters might apply to patent pools with non-SEPs remained unclear.