Bertelsmann said in a statement that its books arm Random House achieved record results in 2012 thanks to the "Fifty Shades" series, which sold 70 million print, audio, and e-book editions between March and December in English, German and Spanish, making it the publisher's biggest-ever bestseller.
"Fifty Shades" is a trilogy of sado-masochistic romance novels by British author E.L. James that has turned into a world-wide hit.
Random House's revenues jumped by 22.5 percent to €2.1 billion ($2.7 billion) and profits, as measured by earnings before interest and tax (EBIT), soared by 75.7 percent to €325 million.
At a group level, Bertelsmann's total sales last year grew by 4.5 percent to €16.065 billion, EBIT was stable at €1.821 billion and net profit rose by 4.1 percent to €484 million.
"Bertelsmann had a solid start to the new year," chief executive Thomas Rabe told the group's annual earnings news conference. But a massive reorganisation meant that business would not grow much this year, he cautioned.
"Given the low overall economic growth in the euro region ... and increased investment in reshaping the group, Bertelsmann expects a stable or slightly declining business performance in 2013," Rabe said.
Nevertheless, "after years where sales declined as a result of portfolio adjustments, the top-line is now expected to rise sharply," the chief executive continued.
"Assuming a slow recovery in the European markets from 2014 and including the planned acquisitions, we're targeting sales of around €18 billion ($23 billion)," Rabe said.
Rabe said two pending transactions -- the combination of Random House with Pearson's Penguin, plus the decision to buy out the US investment fund KKR in their jointly-owned music rights management company BMG -- would "have a positive impact already in this current year."
Once the regulatory approvals had been received, the transactions "will result in significant additions to our revenues," Rabe said, saying sales would then amount to around €17 billion.