Brazilian tycoon Eike Batista's debt-ridden oil firm OGX laid off 20 percent of its 300 employees, the daily Folha de Sao Paulo reported Tuesday.
In a brief statement sent to AFP, the company would only say that it "is involved in a process of financial restructuring."
A week ago, OGX, once the jewel in the crown of Batista's flagging EBX empire, skipped a key 44.5 million interest payment as it scrambled to avoid debt default.
It then said it had 30 days to take necessary measures before the debt matures.
In December, the company must also pay interest on $110 million in notes due in 2018.
Media reports put OGX's debt at $3.6 billion.
If negotiations with creditors fail, OGX is expected to file for bankruptcy protection.
The Economatica consultancy estimated OGX was worth $14.2 billion at the end of last year but put the figure at $1.3 billion at the start of September.
The company has been the worst-hit in the Batista group, forcing him to cast around for new investment to keep his oil projects afloat.
Batista's recent market woes have cut an estimated $30 billion of value from his empire and the man who was once Brazil's richest is now said to be worth only around $900 million.
Batista's EBX has interests in oil, energy, mining, logistics, coal mining and offshore industries.