05/18/2012 05:20 EDT | Updated 07/18/2012 05:12 EDT

SEC seeks information from Chipotle Mexican Grill, Denver-based chain says it's co-operating

DENVER - The U.S. Securities and Exchange Commission has issued a subpoena to Chipotle Mexican Grill Inc. regarding the Denver-based restaurant chain's hiring practices.

Chipotle said Friday that the subpoena it received Thursday requested information regarding its compliance with employee work authorization requirements, plus related information. It says it intends to fully co-operate with the SEC's investigation.

Chipotle has said it is under investigation by federal immigration officials and prosecutors over compliance with employee work authorization laws and regulations.

In 2010, following questions from federal immigration officials, Chipotle fired about 450 Minnesota employees who couldn't prove they were eligible to work in the U.S. Federal officials then requested worker authorization documents for employees in Virginia and the nation's capital. That investigation continues.

The company contends it is following the law.