Chesapeake Energy Corp. /zigman2/quotes/224537584/composite CHK +5.13% announced Thursday plans to repurchase up to $1 billion worth of its common stock and/or warrants to buy back stock over the next two years. The value of the buyback program represents about 15% of oil and natural gas company's market capitalization of $6.68 billion as of Wednesday's close. The stock, which was little changed in premarket trading, has dropped 7.9% amid a four-day losing streak to close Wednesday at a three-month low. "We are pleased to build upon our previously announced base and variable dividend structure to include the ability to repurchase a significant amount of our outstanding equity," said Chief Executive Nick Dell'Osso. The stock has slipped 2.2% over the past three months while the SPDR Energy Select Sector ETF /zigman2/quotes/206420077/composite XLE +3.77% has climbed 10.5% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -1.20% has slipped 0.5%.