Rupert Murdoch's News Corp. has expressed interest in buying book publisher Penguin Group, potentially undermining merger discussions between Penguin and Random House, people familiar with the situation said.

News Corp. is the parent of HarperCollins Publishers, a book publisher whose sales are a little smaller than Penguin's. A combination of the two companies would create the world's biggest consumer-book publisher, accounting for around 20% of English-language consumer-book sales, according to an industry executive.

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