Grifols Set for Biggest Weekly Drop Ever on Short Seller Tumult

Grifols SA shares slumped anew, putting the stock on a pace for its biggest weekly drop ever after a short sellercriticized the Spanish blood-plasma company’s accounting and corporate governance.

Shares of the Barcelona-based company sank 12% Friday to €8.72 at 11:22 a.m. They’re now down almost 40% since Gotham City Research LLC’s report Tuesday. Management efforts to reassure investors have done little to sustain the stock, with the company’s market value shrinking by €3.3 billion ($3.6 billion).

Gotham City said Grifols’s financial statements included earnings from BPC Plasma and Haema, two companies for which Grifols has a call option and that are owned ...