A group including activist investor Carl Icahn has disclosed an 8.18% stake in Cheniere Energy Inc., saying it intends to have talks with the company's management and board about operations, capital expenditures, financing and executive compensation.

Mr. Icahn "may also seek shareholder board representation if appropriate," according to a filing with the Securities and Exchange Commission. As of Wednesday, Mr. Icahn hadn't talked to Cheniere representatives, the filing said.

Mr. Icahn's group, which reported a combined stake of 19.4 million shares of Cheniere, said it believes the stock is undervalued.

The company's share price, down nearly 8% for the year, was up 5.7% at $68.50 in after-hours trading on Thursday.

A Cheniere spokeswoman couldn't immediately be reached for comment.

Houston-based Cheniere is primarily involved in liquefied natural gas-related businesses. It owns the Sabine Pass LNG terminal and Creole Trail Pipeline.

As of March 31, the largest Cheniere shareholder was Viking Global Investors LP, with a holding of 15.4 million shares.

In late 2011, British energy company BG Group PLC agreed to buy LNG from Cheniere on the Gulf Coast to supply Asian and European markets, the first deal of its kind in the U.S. The agreement called for BG to pay Cheniere about $8.2 billion over 20 years. The Sabine Pass terminal in Cameron Parish, La., may begin exporting later this year.

Royal Dutch Shell PLC announced in April that it agreed to buy BG for about $70 billion.

In the second quarter, Cheniere Energy posted a net loss of $142.3 million, or 52 cents a share, narrowing from a year-earlier loss of $280.7 million, or 90 cents a share. Revenue rose to $67.9 million from $66.8 million.

Mr. Icahn's energy holdings have included Chesapeake Energy Corp. and CVR Energy Inc.

Corrections & Amplifications: A group including Carl Icahn has disclosed an 8.18% stake in Cheniere Energy. An earlier version of this article misspelled Cheniere in the second paragraph. (Aug. 6)

Write to Josh Beckerman at josh.beckerman@wsj.com and Maria Armental at maria.armental@wsj.com

Access Investor Kit for "BG Group Plc"

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=GB0008762899

Access Investor Kit for "Royal Dutch Shell PLC"

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=GB00B03MLX29

Access Investor Kit for "Royal Dutch Shell PLC"

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=GB00B03MM408

Access Investor Kit for "BG Group Plc"

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=US0554342032

Access Investor Kit for "Royal Dutch Shell PLC"

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=US7802591070

Access Investor Kit for "Royal Dutch Shell PLC"

Visit http://www.companyspotlight.com/partner?cp_code=P479&isin=US7802592060

Subscribe to WSJ: http://online.wsj.com?mod=djnwires