ZURICH- Swiss speciality chemicals maker Clariant disappointed on Wednesday with stagnant first-quarter profit margins, sending its shares 5 percent lower and leaving analysts wondering whether the company's mid-term profit targets are in reach.

Earnings before interest, taxes, depreciation and amortisation excluding one-time items rose to 268 million Swiss francs ($273 million), compared to a 266 million poll estimate.

That put the operating margin at just 15.6 percent, the same as the first quarter of 2017.

Clariant increased sales by 7 percent to 1.72 billion francs but failed to capitalise on demand to improve profitability. Its natural resources business that sells chemicals to the energy industry suffered yet again, with operating margins falling by more than a full percentage point to 15.2 percent.

Results were "burdened by the continued price consciousness of the oil market", Clariant said in a statement.

"This, however, is expected to improve throughout the year due to the sales pipeline of the business and a generally improving oil market," it said, as crude oil prices hit their highest since 2014. 

Clariant is emerging from a raucous 12 months, after activist investor White Tale scuttled a planned merger with U.S.-based Huntsman Corp.

Saudi Basic Industries Corp (SABIC) then bought White Tale's 25 percent stake, with an update on the companies' plans not due until September. 

Clariant's stock is down 8 percent this year, as Chief Executive Hariolf Kottmann's insistence SABIC will not raise its stake cools investors' takeover hopes.

Wednesday's lacklustre margin added to their gripes.

"We were expecting more operating leverage to kick in, especially at care chemicals and natural resources," Bank Vontobel analysts wrote.

Care chemicals, a division that makes aircraft de-icer and soap ingredients, saw margins rise to 18.4 percent, from 18.2 percent a year ago, while profitability was flat at 16.3 percent in plastics and coatings.

Clariant's fastest-growing business, for catalysts used to accelerate other chemical reactions, boosted the operating margin to 19.8 percent, from 19 percent.

"PRETTY DEMANDING"

Nonetheless, Zuercher Kantonalbank had expected 24 percent and now fears Clariant's overall mid-term target of 16 to 19 percent could be in danger.

"That mid-term margin corridor seems pretty demanding," analyst Philipp Gamper said.

Clariant's Kottmann remained confident the company will hit its 2018 goals of boosting sales and operating profit and also stuck to his mid-term target, for which he has not given a specific time frame.

"We are on track," Kottmann said.

($1 = 0.9823 Swiss francs)

(Reporting by John Miller; Editing by Michael Shields and Dale Hudson) ((J.Miller@thomsonreuters.com; +41 58 306 7734; Reuters Messaging: j.miller.thomsonreuters.com@reuters.net))