British shipping services provider Clarkson PLC announced Wednesday it had been hacked.
"Today, the person or persons behind the incident may release some data," reported the firm.
"In addition, the data at issue is confidential and lawyers are on standby wherever needed to take all necessary steps to preserve the confidentiality in the information."
Clarkson is a major shipbroker and also provides other industry services.
In a statement, Chief Executive Andi Case implied that the hackers were trying to hold its data hostage.
"I hope our clients understand that we would not be held to ransom by criminals, and I would like to sincerely apologise for any concern this incident may have understandably raised,” Case wrote.
Clarkson said it is trying to contact clients and individuals potentially in jeopardy from the breach and emphasized the breach "has not, and does not, affect its ability to do business."
The company said it is working with authorities on the matter and, citing those investigations, has declined further comment.