A hacker collective going by the name TheDarkOverlord is threatening to release data from investment bank WestPark Capital unless it receives a ransom.
The group, which has previously targeted health care organisations, posted a message on Pastebin over the weekend about its latest victim.
The message contains a link to what the hackers claim are a "select few documents" belonging to the California-based bank. Among the 20-odd files are non-disclosure agreements, reports and contracts.
The bank's CEO, Richard Rappaport "spat in our face after making our signature and quite frankly, handsome, business proposal and so our hand has been forced," explains TheDarkOverlord.
In an online chat with Motherboard, a spokesperson for the hackers says: "We are open and available for further communications with Mr Rappaport if he chooses to mitigate what may be to come."