Shares of energy companies were more or less flat amid weakness in commodity prices as investors retreated from economic risk.
Oil futures lost 6% on the week to trade around $37 a barrel.
Oil prices around $40 a barrel are making it more difficult for potential buyers and sellers of energy assets to close deals because it allows for differing views of the industry outlook, said Michael Piazza, a partner at law firm Willkie Farr & Gallagher who specializes in energy deals, as reported earlier.
The number of rigs drilling for oil in the U.S. fell by one to 180 in the latest week, according to oil-field services company Baker Hughes.
Natural gas futures fell about 12% from a week earlier, as traders braced for a prolonged period of oversupply.
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