Media reports at the weekend speculated that the announcement could involve the takeover of Random House, the largest US publisher, or the creation of a publishing joint venture with Havas, the French media group.
Bertelsmann's chairman, Mark Woessner, is inviting journalists to a news conference in Munich this afternoon to unveil "an important strategic corporate undertaking", said Manfred Harnischfeger, head of Bertelsmann public relations.
But Mr Harnischfeger, saying the negotiations were still under way yesterday, declined to elaborate. "We won't say anything before the news conference." he said.
The weekly news magazine, Focus reported that Bertelsmann was expected to take over Random House. A part of Advanced Media, its best-selling authors include Michael Crichton, Norman Mailer and Pope John Paul II.
Such a move would be a continuation of Bertelsmann's strategy to become a leading player in the fiercely competitive US publishing market and strengthen its international book publishing and book club activities.
But a report in the French newspaper Le Figaro steered speculation at the weekend in a different direction. It said the French publishing group Havas and Bertelsmann were negotiating plans to create a joint venture grouping their trade publications. The two companies are already partners in a book club. They are also shareholders in the European broadcasting group CLT-UFA.