A deal could not be reached as the two lenders were not able to sort out issues including structuring and allocating capital, the newspaper reported, citing people familiar with the talks.
Reuters reported in May that discussions stalled between the two banks on a tie-up of their asset management businesses due to differences over who would control the combined entity.
Deutsche Bank declined to comment on the WSJ report. UBS did not respond to a request for immediate comment on Sunday.
(Reporting by Kanishka Singh in Bengaluru, Silke Koltrowitz in Zurich and Chris Steitz in Frankfurt; editing by Jason Neely)