JPMorgan Chase & Co. received subpoenas from the Federal Energy Regulatory Commission (FERC) two times in the past three months as the agency investigates whether the bank manipulated power markets in California and the Midwest, The Financial Times reported, citing court filings.

FERC is inquiring about JPMorgan’s bidding practices, which might have inflated electricity costs by at least $73 million, according to The Times.

The agency is requesting 25 emails that the bank says are privileged. The commission petitioned a federal court on Monday to require the firm to produce the emails.

The commission subpoenaed JPMorgan in April and May seeking unredacted copies of the internal emails, The Times reported. So far, 28 of 53 emails have been released to FERC.

In its most recent quarterly filing with the Securities and Exchange Commission, the firm stated, “JPMorgan Chase’s commodities business owns or has the right to output from several electricity generating facilities. The firm is responding to requests for information in connection with an investigation by FERC regarding bidding practices by this business in certain organized power markets.”

The bank said that it believes it complied with the law, as well as FERC rules, in its practices, The Times reported.

“We have been responding to a FERC investigation into certain activities in our federally approved power business,” Jennifer Zuccarelli, a company spokeswoman, told Bloomberg in an e mail. “We believe we have complied in all respects with the law, as well as FERC rules and applicable tariffs, governing this market.”

FERC began the investigation last year after the California and Midwest markets informed the government of bidding practices the markets “viewed as abusive,” according to one court filing cited by The Times.

The commission is inquiring whether the bidding practices elicited “inflated” or “excessive” payments from two wholesale power markets that serve California and some Midwest states.

“Any such improper payments to generators are ultimately borne by the households, businesses, and government entities that are the end consumers of electricity,” FERC attorney Thomas Olson wrote in the court papers, according to The Times.

FERC lawyers are also investigating whether the firm breached a “rule requiring truthful and non-misleading communications” to regulators, a court filing stated.

In an email from March 2011 included in the court filings, Francis Dunleavy, head of principal investments of JPMorgan’s global commodities group, wrote to the head of the group that he will deal with one regulatory inquiry, “but it may not be pretty,” The Times reported.

In March, FERC accepted a record $245 million settlement from Constellation Energy regarding allegations the firm’s traders scheduled physical flows of electricity at a loss in order to receive a greater profit on derivative positions, Reuters reported.

After the settlement, FERC commissioners told Reuters the agency was adding staff with more analytical skills and energy market experience to allow the enforcement division to investigate further into trading data and make it harder for trading firms to manipulate natural gas and power markets.