Hogan Lovells Partner Eduardo Ustaran, CIPP/E, and Senior Associate Dan Whitehead assess the Court of Justice of the European Union advocate general's opinion on the EU General Data Protection Regulation's one-stop-shop mechanism. While the opinion upholds the role of the lead supervisory authority as the primary investigator in data protection cases, the attorney general laid out circumstances in which supervisory authorities concerned could take action, such as instances when processing is necessary for compliance with legal obligations or should the LSA decide not to handle a case. Editor's note: IAPP Staff Writer Joe Duball wrote about the reaction to the opinion for The Privacy Advisor.