Chesapeake Energy Corp. says the federal government is investigating whether there were antitrust violations relating to its purchase of some oil and gas land in Michigan.
The stock lost 3 percent in morning trading Friday.
The Oklahoma City-based company said in a regulatory filing on Thursday that it was subpoenaed by the U.S. Department of Justice to hand over paperwork related to those purchases. Chesapeake says it has also received demands for documents and information from state government agencies.
It said it intends to cooperate while its board conducts an internal investigation.
Chesapeake has spent about $400 million to buy leases in Michigan.