The Delaware Court of Chancery on Wednesday ordered UnitedHealth Group Inc. to turn over to stockholders a wide range of corporate documents, including information referenced in a whistleblower suit outlining a supposed scheme to overbill Medicare by possibly “billions of dollars.”

The ruling from Vice Chancellor Tamika Montgomery-Reeves granted Amalgamated Bank and two pension funds most of the document demands they sought in conjunction with an investor probe into Medicare payments made over a 12-year period.

However, she did limit the scope of the inspection after the Minnesota-based health care company challenged the investors' rights to the records at trial in January.

UnitedHealth had argued that the investors could not rely solely on the allegations in the sprawling complaint under the False Claims Act, initially filed by the former director of finance at a UnitedHealth subsidiary. The plaintiffs, the company argued, had not established a credible basis for wrongdoing because the underlying conduct was not illegal.

But Montgomery-Reeves said the 78-page U.S. Department of Justice complaint pulled from depositions of 20 UnitedHealth employees and more than 600,000 documents the company produced during a five-year investigation of its billing practices, indicated that the company's top brass, including CEO Stephen Hemsley, knew about the alleged overbilling.

“The evidence also suggests that defendant did not engage in steps to correct the inaccuracies or alert Medicare of the previous payments it received based on faulty coding,” she wrote in a 28-page memorandum opinion.

“Defendant cannot escape the testimony and documents that demonstrate a credible basis for this court to infer possible wrongdoing or mismanagement simply because they are referenced in a complaint.”

Among the information that would be provided to the plaintiffs were documents related to director independence, board meetings and policies and procedures. The most controversial request, however, centered on eight years of emails between five senior-level officers, which went beyond the documents referenced in the DOJ complaint.

Montgomery-Reeves said email communications are generally produced only in exceptional circumstances, and the plaintiffs did not clear the higher bar for showing that production is appropriate.

“Given the amount of information plaintiffs are receiving, they have not shown why additional communications of five custodians across an eight-year span is necessary for their investigation,” she said.

“The have not met their burden of showing that additional email communications from these particular officers are necessary to their investigation.”

Attorneys from both sides of the Delaware action were not immediately available to comment on Thursday.

The book-and-records case, filed in September, followed a whistleblower suit last July from Benjamin Poehling, who alleged violations of the False Claims Act dating back to 2006. The DOJ quickly intervened alleging that UnitedHealth had been violating both the FCA and Medicare regulations since 2005, despite repeated warnings from the government.

UnitedHealth has moved to dismiss that suit in the U.S. District Court for the Central District of California. The company denied any wrongdoing.

The Delaware case was captioned In Re UnitedHealth Group Section 220 Litigation.

The plaintiffs were represented by Jeroen van Kwawegen, Christopher J. Orrico and David MacIsaac of Bernstein Litowitz Berger & Grossmann; Norman Berman, Nathaniel L. Orenstein and Mark Delaney of Berman Tabacco; Jessica Zeldin and P. Bradford deLeeuw of Rosenthal, Monhait and Goddess; and Nathan A. Cook of Grant & Eisenhofer.

UnitedHealth was represented by R. Judson Scaggs Jr., Lauren Neal Bennett and Jason Z. Miller of Morris, Nichols, Arsht & Tunnell.