Ethane frac spread margins took large hits at Conway and Mont Belvieu in August as natural gas liquid (NGL) and natural gas feedstock prices fell across the board due to the economic uncertainty caused by Standard & Poor’s decision to lower the United States’ credit rating.

Feedstock prices dropped 8% to $3.93 per million Btu (/MMBtu) at Conway and 11% to $3.91/MMBtu at Mont Belvieu. In comparison to feedstock prices, NGL prices performed better at Mont Belvieu and worse at Conway for the month. The theoretical NGL barrel price dropped ...