FRANKFURT, Aug 28 (Reuters) - Abu Dhabi National Oil

Company (ADNOC) is finishing due diligence for a takeover of

Covestro ( CVVTF ) in a deal that could reach 11.7 billion euros

($13.00 billion), two sources familiar with the matter told

Reuters on Wednesday.

"The big questions have been clarified," one of the sources

said, as the deal enters its final phase. An announcement could

come in September, with a price of 62 euros per Covestro ( CVVTF ) share

still on the table, the sources said.

Covestro ( CVVTF ) and ADNOC declined to comment. Bloomberg first

reported the news on Wednesday.

($1 = 0.9001 euros)