* Deal could be struck before the end of October -source
* Macquarie close to buying investment bank -sources (Recasts with source's comments on Deutsche Bank deal)
FRANKFURT, Oct 20 (Reuters) - Deutsche Bank looks set to buy a stake of about 75 percent in Sal. Oppenheim for about 1 billion euros ($1.5 billion) as soon as next week, a person familiar with the matter told Reuters on Tuesday.
Deutsche is looking at all Sal. Oppenheim assets apart from the investment bank, the person said, although it remains unclear whether the bank would also buy a private equity fund controlled by Sal. Oppenheim's owners.
Details of the deal are still under negotiation.
The outlines of a deal could be presented around the same time as Deutsche Bank earnings, the person said, marking an additional acquisition for Germany's largest bank, which is already in talks to buy parts of ABN Amro and Deutsche Postbank .
Deutsche Bank's supervisory board is set to discuss the acquisition a day before the bank's third-quarter earnings report on Oct. 29.
Sal. Oppenheim's family owners are selling parts of the business after the bank posted its first post-war loss last year, hurt by the financial crisis and a hit from its stake in insolvent German retailer Arcandor.
Deutsche has already stepped in to provide 650 million euros in loans to help prop up the struggling wealth manager.
If Deutsche's acquisition goes through it marks another step in a wave of consolidation of the European private banking industry.
Wealth management, until 10 years ago a nice add-on for many universal banks with the exception of the two Swiss giants UBS and Credit Suisse, has grown in importance among global banks and many are scrambling to acquire private banking assets.
Australia's Macquarie Group Ltd is close to clinching a deal to buy Sal. Oppenheim's investment banking arm, other sources close to the matter told Reuters on Tuesday.
A deal to sell the investment bank could be struck as early as the end of the month, one person said.
Representatives from Macquarie have already met with Sal. Oppenheim's works council, two people familiar with the matter said. Macquarie wants to reassure the investment bank's 450 staff to prevent an exodus before any deal, the sources said.
Macquarie is in exclusive talks with the German bank, which is headquartered in Luxembourg, after Italy's Mediobanca withdrew from the bidding for Sal. Oppenheim's investment banking arm on Oct. 1.
Deutsche Bank could initially buy all of Sal. Oppenheim and then split off the investment bank at a later stage, people familiar with Deutsche Bank's thinking have told Reuters.
Deutsche Bank, Sal. Oppenheim, and Macquarie all declined to comment.
News of talks between Macquarie and Sal. Oppenheim's labour representatives first appeared in German daily Boersen-Zeitung. (Reporting by Philipp Halstrick and Alexander Huebner, writing by Edward Taylor; Editing by Rupert Winchester) ($1=.6678 Euro)