BARCELONA, Jan 11 (Reuters) - Spanish pharma company Grifols sees no problem closing the sale of a stake in Shanghai RAAS despite the market impact of a negative report by Gotham City Research that questioned its accounting, which Grifols top brass said was "absolutely wrong".

Vice-chair Raimon Grifols told a conference call with investors on Thursday $1.8 billion deal should be closed as planned in the first half of this year. The proceeds will be used to reduce Grifols' debt.

CEO Thomas Glanzmann said there was room to improve communications and governance of the company, but said the short-seller fund Gotham City had only been after financial gain and used information to suggest wrongdoing that had already been signed off by auditors and regulators.

Still, company shares fell as much as 12% in Thursday afternoon trading.

Grifols

said on Wednesday it would launch legal action against Gotham City Research whose report wiped $2.5 billion off the Barcelona-based firm's market value on Tuesday.

Chief Financial Officer Alfredo Arroyo Guerra told the same call the company was working to simplify its structure and transactions with its holding firms, so "it will be plain vanilla in the future".

Company officials said they would provide information requested by Spanish stock market supervisor CNMV "as soon as possible" and within the 10-day deadline.

(Reporting by Joan Faus, writing by Andrei Khalip, editing by Aislinn Laing)