The district court abused its discretion in denying Volkswagen’s motion to intervene in a FOIA action seeking production of documents concerning Volkswagen’s dieselgate fraud. Volkswagen satisfied Fed. R. Civ. P. 24(a)’s three requirements for intervention as of right. It had a significant protectible interest in asserting that the sought documents were exempt from FOIA disclosure under Exemption 4. A ruling in Kalbers’ favor directing disclosure of those documents would impede Volkswagen’s ability to protect its interest. And Volkswagen was better situated than the DOJ to explain why the exemption applied. The trial court also wrongly held that Volkswagen had waited too long to move to intervene. In evaluating delay, the clock starts when the intervener has reasonable cause to believe its interests won’t be protected by the existing parties, not from the earlier time it first learns of the litigation. Kalbers would suffer no cognizable prejudice from the intervention. The fact that adding a party would complicate the litigation didn’t count as prejudice, and Kalbers wasn’t prejudiced by anything having to do with the intervention motion’s timing. The motion was also made at an early stage of the case. All of these factors weighed in favor of intervention.