BRUSSELS/FRANKFURT (Reuters) - A decision by Amazon and Apple to scrap all exclusivity obligations in the supply and distribution of audiobooks will likely boost competition, EU antitrust regulators said on Thursday.

The companies announced their decision on Jan. 5 after talks with the European Commission and the German Federal Cartel Office. Such curbs had prompted a complaint from the German Publishers and Booksellers Association to both regulators, triggering an investigation by the German enforcer in November 2015.

"The European Commission welcomes an agreement to end all exclusivity obligations concerning audiobook supply and distribution between Amazon's subsidiary Audible and Apple," the EU competition authority said in a statement.

The German cartel office said on Thursday it had closed its investigation into Apple and Amazon. The watchdog said that there was no further reason to continue the investigation.

The probe started at the end of 2015, sparked by a complaint from the German publishers and booksellers lobby, who said Amazon and Apple were abusing their dominant market position.

The publishers and booksellers said more than 90 percent of all downloads of audio books in Germany were made via the Audible or Amazon sites, or via the iTunes store, which was exclusively supplied by Audible.

"With the deletion of the exclusivity agreement Apple will now have the opportunity to purchase digital audiobooks from other suppliers," Andreas Mundt, president of the German cartel office, said in a statement.

"This will enable a wider range of offer and lower prices for consumers," he added.

(Reporting by Foo Yun Chee and Harro ten Wolde; Editing by Julia Fioretti)