* 2013 net profit 478 mln eur vs poll avg 488 mln
* Earnings hit by settlement costs for U.S. investigation
* CEO says macroeconomic environment improving
FRANKFURT, Feb 19 (Reuters) - German exchange operator Deutsche Boerse said it would keep its dividend stable even after a legal settlement and shaky revenue pushed 2013 net profit down by a fourth.
Deutsche Boerse, which has been battling subdued trading volumes on its exchanges in the wake of the euro zone debt crisis, was hit hard last year by 129 million euros ($177 million) in costs linked to settling an investigation into the possible violation of U.S. sanctions against Iran.
In addition, it spent nearly 90 million euros last year on a cost saving programme, which also hurt earnings.
The company on Wednesday said full year net profit fell to 478 million euros from 645 million in 2012, slightly below the 488 million average expectation in a Reuters poll.
Its shares were down 1.5 percent in late Frankfurt trade .
Deutsche Boerse plans to propose keeping its dividend for 2013 stable at 2.10 euros per share, it said.
Chief Executive Reto Francioni said he was upbeat about growth prospects after net revenue fell by only 1 percent to 1.912 billion euros, despite challenging conditions.
“The macroeconomic environment in Europe is also showing signs of improvement,” Francioni said in a statement.
“As a result, we are optimistic about the future,” he said, without giving concrete forecasts for this year. Francioni is due to hold a news conference on Thursday at 0900 GMT to talk about the results.
The company said it would boost investment in growth and infrastructure by around 30 million euros in 2014, focusing on expanding the company’s presence in Asia.