Shares of Chesapeake Energy Corp. /zigman2/quotes/201364537/composite CHK -30.48% swung to a sharp loss in very active morning trading Tuesday, putting them on track for a 20-year closing low, in the wake of the oil and gas company's wider-than-expected second-quarter loss. The stock tumbled 9.9%, erasing a gain of as much as 6.4% just after the open, to trade at the lowest price seen since April 1999. Volume of 31 million shares makes the stock the most actively traded on major U.S. exchanges. The company reported that it swung to net income in the second quarter, but also adjusted loss per share of 10 cents a share, which was wider than the FactSet consensus of a loss of 6 cents a share. SunTrust Robinson Humphrey analyst Neal Dingmann said, despite "solid" 2019 guidance and reduced liquidity concerns following a refinancing, he remains worried about the more than $10 billion worth of debt and continued cash flow outspend. The stock has plunged 51.4% over the past three months, while the SPDR Energy Select Sector ETF /zigman2/quotes/206420077/composite XLE -3.02% has shed 9.4% and the S&P 500 /zigman2/quotes/210599714/realtime SPX -0.38% has slipped 2.4%.