A number of health insurers say they are cooperating with a New York official’s requests for information about their health care cost reimbursement practices.

New York Attorney General Andrew Cuomo told the Associated Press Thursday that he has issued new subpoenas to insurers such as Aetna Inc., Hartford; CIGNA Corp., Philadelphia; the UnitedHealth Group Inc., Minnetonka, Minn.; and WellPoint Inc., Indianapolis.

The subpoenas are part of an investigation announced in February of allegations that insurers have been shortchanging consumers by intentionally using unrealistically low estimates of “reasonable and customary” rates.

Many plans say they will reimburse members who seek care out of network for 50%, 70% or some other share of the reasonable and customary rates for that type of care.

Cuomo says he is seeking testimony from insurers’ chief executives about their companies’ use of data from Ingenix, a UnitedHealth care unit that collects medical payment data. Cuomo alleges that the companies may be using the data to set payment rates for out-of-network medical providers that are significantly below what the providers actually charge for their services.

UnitedHealth, says it is “in the midst of ongoing discussions with the attorney general’s office, and we will continue to cooperate fully.”

The company says it “is committed to fair and appropriate payment for physicians, the state’s other health care providers and consumers. The company also believes in delivering high quality and dependable database tools. The reference data is rigorously developed, geographically specific, comprehensive and organized using a transparent methodology that is very common in the health care industry.”

UnitedHealth says health care payers use Ingenix reference tools to negotiate their own reimbursement schedules independently, to establish fees for out-of-network care, to negotiate provider contracts and to review claims.

A spokesman for Independent Health Association, Buffalo, N.Y., says his company also is cooperating with the investigation.

“Independent Health has worked collaboratively with the attorney general’s office, including our most recent agreement with Attorney General Cuomo to adopt the model code for doctor ranking programs,” says IHA spokesman Frank Sava.

“We look forward to continuing our good working relationship with the attorney general and intend to cooperate fully in this matter,” Sava says.

A CIGNA spokesman says the company “will be responding appropriately to the subpoenas.”

New York insurers Group Health Inc. and Health Insurance Plan of New York had no comment.

Representatives for several other insurers involved in Cuomo’s investigation were not immediately available for comment.