Petrobras, the state-run oil company at the center of a kickback scandal in Brazil, said it is under investigation by the U.S. Securities and Exchange Commission (SEC) and will provide related documents.

The SEC sent Petrobras a subpoena on Nov. 21 and the Rio de Janeiro-based company will send the information after two law firms complete an internal probe, Petrobras said in a statement. Last month, it hired Trench, Rossi & Watanabe Advogados and Gibson, Dunn & Crutcher to examine former director Paulo Roberto Costa’s accusations of bribes and overpriced contracts.

Petrobras, which has tumbled 17% this year and is the worst performing major oil stock in the past four years, has had two former directors arrested since March for alleged involvement in a multibillion-dollar laundering and bribery case dubbed Car Wash. The company said last week it would release unaudited third-quarter results by Dec. 12, a month later than originally scheduled, because it needs to make adjustments to account for corruption-related cost inflation.

“Typically, an investigation would be done in parallel and collaboratively” among U.S. and Brazilian authorities, said Jason Flemmons, managing director at FTI Consulting Inc. in Washington, and the former deputy chief accountant of the Division of Enforcement for the SEC. “I wouldn’t expect the SEC or DOJ to sit back and wait for Brazilian authorities to complete their investigation first.”

Auditor Hurdle

Judy Burns, a spokeswoman for the SEC, declined to comment when contacted by Bloomberg News.

Petrobras needs the approval of its auditors to be able to issue bonds. Petrobras has relied on overseas bond buyers for more financing than any company in emerging markets in the past three years, raising $44.5 billion since 2011.

The Car Wash case spread to Petrobras earlier this year after investigators uncovered ties between Costa, the company’s former head of refining, and a black-market money dealer. Costa later told police he received bribes from a group of construction companies and shared the proceeds with politicians who are part of the ruling coalition. Parties in the coalition and building companies have denied the allegations.

Petrobras has said it’s a victim in the scheme and is working to recover money lost to graft. It is setting up a compliance division to improve corporate governance and may have to reduce the value of some assets where graft inflated costs, CFO Almir Barbassa said Nov. 17.