German media giant Bertelsmann said Monday it expects sales and underlying earnings to increase in the whole of 2015 after a strong first half of the year.

"Bertelsmann achieved strong growth in revenues, operating (profit) and net income in the first half of 2015," the group said in a statement.

"We are very satisfied with the development of the past months," said chief executive Thomas Rabe.

"Bertelsmann is in excellent financial shape. Our businesses' high level of profitability gives us scope for investment. If there is no downturn in the global economy, we expect higher revenues and operating (profit) for the full year. In the medium term, we intend to significantly increase group net income towards one billion euros" ($1.1 billion), he said.

In the first six months, net profit jumped by 55 percent to 398 million euros. Operating or underlying profit, as measured by earnings before interest, tax, depreciation and amortisation, climbed by 4.4 percent to 1.063 billion euros and revenues rose by 2.5 percent to 8.04 billion euros.

Bertelsmann, which is family owned and not listed on the stock exchange, owns the television group RTL, book publisher Penguin Random House and magazine publisher Gruner + Jahr.