In an interview with Forbes, Assange said the site will post tens of thousands of internal documents that will make public the internal dealings of a major U.S. bank, Forbes reported Monday.
Assange would not say which bank will be subject to the exposure, but he said the document release would illustrate bad behavior within banking.
"You could call it the ecosystem of corruption," he said. "But it's also all the regular decision making that turns a blind eye to and supports unethical practices: the oversight that's not done, the priorities of executives, how they think they're fulfilling their own self-interest."
WikiLeaks released more than 250,000 cables this weekend that include embarrassing comments about foreign leaders and U.S. operations abroad. Both the White House and Secretary of State Hillary Clinton reached out to foreign leaders after the documents were published.
No large companies responded to a Forbes request for comment, and the U.S. Chamber of Commerce declined comment on Assange's assertion that WikiLeaks will blow the whistle on a major bank.
James Lewis, a former U.S. Commerce Department official who analyzes cybersecurity for the Center for Strategic & International Studies, told Forbes WikiLeaks document dumps present companies with a "reputational risk" they "didn't have to think about a year ago."