The Rosenholz files are a collection of 381 CD-ROMs containing 280,000 files with information on persons who were as sources and targets or employees and helpers in the focus of the Hauptverwaltung Aufklärung (HVA), one of the intelligence agencies of the former GDR. At the beginning one thought that the files mostly contain the real names of agents who worked for the HVA in former West Germany. Later it came clear that at least 90% of the persons never worked for or with the HVA. 
The Rosenholz files ended up with the CIA during the German reunification under unclear circumstances; they were initially analysed by the USA only, but finally returned to Germany in 2003 after long negotiations. The exact reason for the duration of the negotiations is still debated among scholars. 
According to the annals of the former Moscow CIA station chief Milton Bearden, the Rosenholz files were not seized on January 15, 1990, when demonstrators stormed the Ministry of State Security (GDR) in Berlin, but instead only when former US president George H. W. Bush personally contacted the chief of the Berlin CIA station. Bearden later on lobbied for the return of the Rosenholz files to the German Bundesbeauftragte für die Unterlagen des Staatssicherheitsdienstes der ehemaligen Deutschen Demokratischen Republik (BStU) while CIA station chief in Bonn, and received the German government's Bundesverdienstkreuz for this.
After being returned, the files were checked for mistranslation and other errors by the BStU; since March 2004, the files have in theory been open to the general public and can be viewed following an appropriate request (Antrag auf persönliche Akteneinsicht). In fact according to the unclear compilation of the files many requests were turned down. 
- On the Rosenholz files on BstU's website
- Livingston, Gerald (March 2006). An Operation Called 'Rosenholz' - How the CIA bought the Stasi files for $75,000. Atlantic Monthly.