More than 100 organizations’ private documents that included financial data were downloaded from a Web portal of the U.S. Department of Homeland Security this month.

“This letter is to inform you that your company’s bank account information may have been improperly accessed because of this incident,” DHS privacy officer Christopher Lee said in a letter sent to the organizations earlier this month. “The incident appears to have occurred sometime over the prior four months.”

The organizations had bid on a 2013 contract to help DHS’ Science & Technology team develop new communications technology for first responders. Unnamed, unauthorized persons outside of the agency downloaded the documents from a department Web page. The source of the access is unknown.

Sixteen organizations had bank information on potentially accessed documents, and all 114 were notified promptly by Science & Technology with a list of their accessed documents, a DHS spokesperson said. The documents, 520 in all, included proposals, decision notification letters, documents regarding contract and award deliverables, and other supporting materials. The accessed portal is run by Herndon, Va.-based REI Systems Inc. The company did not immediately comment Thursday on whether the unauthorized access affected other government projects as well as the DHS data. REI provides technology services to other divisions of the government, including the Department of Health and Human Services, the Department of Justice, the General Services Administration, the Internal Revenue Service, NASA and the Federal Aviation Administration.