Connecticut Insurance Commissioner Andrew Mais on Tuesday rebuffed Attorney General William Tong who urged the state Insurance Department to halt a planned Aug. 15 public hearing reviewing double-digit rate increases sought by health insurers.

Tong asked the agency to wait as Congress considers extending a tax credit he said could reduce the need for higher prices.

In a letter to Mais, Tong said the U.S. Senate is expected to debate and vote this week to extend tax credits that Anthem Health Plans and ConnectiCare Benefits Inc. assumed would expire Jan. 1.

The two insurers and state Insurance Department believed a Jan. 1 expiration of the tax credit was a “significant driver” behind the rate increase requests, he said.

“The tax credit extension would be a game changer and may significantly reduce the need for an increase,” the attorney general said. “It would be a dereliction of our duty to consumers to proceed with a hearing on rates built on what now appears to be a bad guess.”

If Congress extends the Federal Advance Premium Tax Credits, rate increase requests must be revised and would reflect substantial savings to consumers, Tong said.

In his response to Tong, Mais rejected as inaccurate the argument that the end to the subsidies Dec. 31 would drive the double-digit rate increase requests. The expiring tax credits were never identified in the rate filings as a “significant” cost driver, he said.

The Aug. 15 meeting will proceed, Mais said.

The federal Centers for Medicare and Medicaid Services and the insurance carriers must have their rates set by early September for the health exchange to be prepared for open enrollment set to begin Nov. 1, he said.

Spokeswoman Kimberly Kann said ConnectiCare supports the advocacy by Gov. Ned Lamont, the state’s congressional delegation and advocacy groups to continue the Advanced Premium Tax Credits provided in the American Rescue Plan Act. The enhanced tax credits help make insurance coverage affordable, she said.

ConnectiCare will monitor the regulatory environment and update its requests as appropriate, Kann said.

Anthem Blue Cross and Blue Shield in Connecticut said its rates will reflect its experience and ability to “deliver on behalf of consumers in this market.”

“This premise will guide our next steps as we learn more and we will continue to work with the state as the regulatory process continues,” the insurer said in an email.

Insurance companies that sell policies on and off Connecticut’s Affordable Care Act exchange submitted proposals in July seeking an average increase of 20.4% on individual health plans next year. On small group plans, the carriers are asking for an average increase of 14.8%.

The proposals drew criticism from several state lawmakers and health care and consumer advocates who said the increases were excessive and could hamper health care access. Critics have said steep health insurance cost increases are not sustainable as consumers already struggle with the highest rate of inflation in 40 years.

ConnectiCare cited medical and pharmaceutical costs and the continued impacts of COVID-19 on members’ use of services, including obtaining delayed care.

Tong and other elected officials last month asked the Insurance Department to schedule a formal hearing as a forum to question insurance executives and present an independent analysis. Mais rejected the suggestion, saying the Insurance Department will schedule a rate hearing as it has in the past, taking testimony from consumers, consumer advocates, elected officials and other interested parties.

U.S. Sen. Chris Murphy, D-Conn., said the tax credits will cut the cost of prescription drugs for seniors. And U.S. Sen. Richard Blumenthal, D-Conn., urged the Insurance Department “to aggressively review these proposed rate hikes that are beyond unaffordable.”

Stephen Singer can be reached at ssinger@courant.com.