MADRID, March 6 (Reuters) - Shares in Spanish drugmaker Grifols fell nearly 15% in early trading on Wednesday following the publication of a new report by Gotham City Research questioning the Barcelona-based company's "transparency, integrity and ethical conduct".

Since early January, the short-sheller has repeatedly accused Grifols of manipulating its financial accounts, wiping billions of euros off the firm's market value.

Grifols has previously denied Gotham City's accusations, saying it had already replied to all of the questions raised in the latter's reports. It declined to comment on the most recent claims.

Gotham said on Wednesday that Grifols had muddled the nature of a 319 million euro ($346.6 million) loan in its 2022 annual report.

Grifols labelled the loan under "other financial assets with other related parties", but Gotham said it was lending activity specifically between Grifols and Scranton Enterprises, the Grifols' family entity, as part of a cash pooling financing arrangement.

Gotham said Grifols' representation of the loan was "neither detailed, nor correctly identifies the nature of the transactions".

The hedge fund added that it believed that the "cash pooling revelation" was new information, "thus indicating that Grifols' claim that it had already answered our questions was incorrect".

Grifols said in January it had filed a lawsuit in a U.S. court against Gotham City's founder Daniel Yu and his company, seeking damages over a report suggesting accounting irregularities.

($1 = 0.9204 euros)

(Reporting by David Latona; Additional reporting by Inti Landauro and Emma Pinedo; Editing by Jan Harvey)