Sales and earnings at Penguin Random House both fell by more than 10% in the first half of 2016 compared to the same period in 2015. PRH parent company Bertelsmann reported that revenue at the trade publisher fell 10.7% in the first six months of 2016, to 1.52 billion euros, while EBITDA (earnings before taxes, interest, taxes, depreciation, and amortization) fell 10.6%, to 185 million euros.

Bertelsmann attributed the decline to the expected drop in e-book sales in the U.S. and U.K. due to changed retail terms, as well as the negative impact of currency exchanges. Partially offsetting those negative trends were steady physical book sales and gains in downloadable audio sales.

In a detailed letter to employees, PRH CEO Markus Dohle observed that the “past eight months have been an unusual time, full of ups and downs around the world and in our industry.” He attributed part of the drop in sales to a lack of mega-bestseller on the order of The Girl on the Train and Grey, which helped to drive revenue last year. He also pointed to a drop in e-book revenue as a reason for the sales decline, but noted that sales of digital audiobooks have had “a significant upswing.”

Another encouraging sign, Dohle said, is the “strength and stability of our physical book sales.” He reminded employees that PRH always believed that print would remain an important part of publishing and noted that the investment the company made throughout its physical supply chain “is especially paying off now as consumer demand for physical remains robust.”

Dohle said that with the integration of Penguin and Random House completed, “we can increasingly enhance our emphasis on our readers, setting new priorities and putting our plans into action. Our initiatives include developing new approaches to driving discovery online for our books and deploying new technologies across all marketing channels—social, email, web, and print campaigns—to reach and influence more readers than ever before.”

Looking at the balance of 2016, Dohle said July sales were good, but said the company sees a number of unknowns ahead. He closed the letter by noting: “What will be the future effects of Brexit? Will our hopes for recovery happen for some challenged Latin American local economies? What will be the results of the unprecedented U.S. presidential election? As publishers, we are no strangers to uncertainty. On the contrary, an ever-changing market landscape is what we know how to navigate steadily. This is why I am optimistic we will finish the year with another consistent, solid performance—creatively and fiscally.”