MADRID, May 14 (Reuters) - Grifols shares were down 3.9% on Tuesday morning following the publication of a new report by short-seller Gotham City Research which again questioned the Spanish drugmaker's "commitment to transparency, integrity and ethical conduct".

A spokesperson for the Barcelona-based company did not immediately respond to a request for comment.

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

Grifols has previously denied Gotham City's accusations, saying it replied to all of the questions it raised.

In the report released on Tuesday, Gotham City Research questioned the accounting treatment of loans worth 266 million euros ($287 million) involving Scranton Enterprises, the Grifols' family entity, and Grifols units.

($1 = 0.9272 euros) (Reporting by Inti Landauro and Jesus Aguado; editing by Jason Neely)