The nation's largest health care group has offered to pay a record $745 million to resolve the civil portion of a massive federal investigation into possible fraudulent billing practices by the firm, Columbia/HCA Healthcare Corp., the New York Times reports.

The central focus of the various investigations is whether Columbia/HCA hospitals and home health services "padded" billings to federally-funded programs including Medicare, billed for unneeded tests, and/or had unlawful financial agreements with physicians, the Times reports.

If approved, the settlement would be the largest medical fraud settlement in American history, by a wide margin.

Part of the agreement, however, depends on whether Columbia/HCA can resolve the ongoing criminal investigation by the end of this year. The proposed settlement calls for a Dec. 31 resolution of the criminal cases. If this doesn't happen, the company can withdraw its settlement and either negotiate a new agreement or face trial, the newspaper reports.

Regardless of the outcome of the various civil and criminal inquiries, Columbia/HCA has a track record of generating controversy within the health care industry and in the communities where they have facilities.

The chain had until recently been on a years-long buying spree, purchasing a number of nonprofit hospitals and medical facilities and converting them to for-profit operations. In 1998, the company announced it was asking for property tax cuts and refunds for hospitals it owned in northern Virginia, a request that drew widespead criticism from nonprofit leaders and local government officials.

The majority of Columbia's problems allegedly took place during the tenure of former Chairman Richard L. Scott, who was forced to resign following government raids of company offices three years ago. Scott was replaced by Dr. Thomas Frist Jr., co-founder of the Hospital Corporation of America chain, the Times reports.