Pacific Investment Management Co. (PIMCO) has joined a long line of investors alleging losses as a result of a corruption scandal that has engulfed Brazil’s troubled state-run oil company.

Pimco claims in a lawsuit that Petroleo Brasileiro misled investors about the extent of the scandal, which has wiped billions of dollars in value from Petrobras’ books. The company’s shares have fallen more than 64% in the past year.

Petrobras has long maintained it was a victim of suppliers, a few insiders, and local politicians who prosecutors say fleeced the company for at least $2 billion. But Pimco alleges Petrobras executives knew of the corruption scheme, which “ultimately calls into question the integrity of the company as a whole.”

The suit “is yet more bad news for Petrobras as it struggles to restore its reputation and sell assets to reduce its ballooning debt pile,” The Wall Street Journal said.

More than a dozen lawsuits have been filed by U.S. investors who bought American depositary receipts sold by Petrobras in New York, including the Gates Foundation Trust, the attorney general of Ohio, public pension funds in Idaho and Hawaii, and the city of Providence, R.I.

Petrobras is the world’s most indebted company and has been a central emerging market investment for U.S. asset management companies. The New York Times reported a year ago that Pimco was the largest holder of Petrobras’ debt.

“Few emerging market companies are as widely held by equity and bond investors as Petrobras, long seen as a benchmark play for investors looking for exposure to fast-growing developing markets,” The Times noted.

But so far this year, Petrobras’ credit ratings have been downgraded to junk status by both Moody’s Investors Service and Standard & Poor’s Ratings Services. The company is now working to sell some $58 billion in assets through 2018 to raise cash and deal with its debt.