ProSieben's shares, recently dropped from the DAX index of leading German companies <.GDAXI>, fell 9 percent on the results to make them the worst performer among national midcaps.

"The comments about EBITDA falling in Q2 and Q3 may raise issues about the need for Q4 to perform," said analysts Ian Whittaker and Annick Maas at Liberum, who have a "hold" rating on the stock.

Chief Executive Thomas Ebeling stepped down early in the year after completing a restructuring at ProSieben that bundled its e-commerce activities and brought in investor General Atlantic to help develop the business.

The transition is not complete, however, with his designated successor Max Conze, the former CEO of UK appliances maker Dyson, not due to take up his role until next month.

On a conference call, interim CEO Conrad Albert said ProSieben's annual targets of revenue growth in the low- to mid-single digits, and stable adjusted EBITDA margins in the mid-20s percent range, were still achievable.

But investors took fright at a warning that adjusted EBITDA would weaken in the second and third quarters, due to seasonally higher programming costs and consolidation effects, before picking up in the fourth quarter.

Munich-based ProSieben said first-quarter adjusted earnings before interest, taxation, depreciation and amortization (EBITDA) rose 7 percent to 200 million euros (175 million pounds), just beating the 5 percent gain seen by analysts in a Reuters poll.

That was sustained by a good showing at ProSieben's main commercial TV channels. The content product and global sales division - for which the company is seeking a partner - suffered a drag on revenues as the dollar weakened, however.

ProSieben's e-commerce division, called Nucom, also saw declines in revenues and profits. This was due to asset disposals over the course of the last year, the company said.

Chief Financial Officer Jan Kemper said that ProSieben's leverage had declined to 1.5 times core earnings from 1.8 times over the quarter, leaving room for two or three acquisitions in the second half of the year.

First-quarter revenues declined by 3 percent to 881 million euros, in line with expectations, although the company said that, adjusted for consolidation and currency effects, revenues had risen by 1 percent.

(Reporting by Joern Poltz; Writing by Douglas Busvine; Editing by Keith Weir)