NEW HAVEN, Conn. (AP) — Connecticut officials have launched an investigation into allegations of market power abuse by two of the state's largest energy providers.

The Office of Consumer Counsel says the investigation began after university researchers claimed Eversource and Avangrid companies intentionally created natural gas shortages so they could drive up energy rates.

The report by university researchers estimates the practice cost utility customers billions of dollars over a three year period.

Eversource representative Tricia Taskey Modifica said Tuesday the report is a "complete fabrication." She says the company is "always acting in the best interest of our customers."

Avangrid says their gas supply portfolios and gas pipeline contracts are consistent with industry standards.

The Public Utilities Regulatory Authority is expected to call for a hearing in the upcoming weeks.