U.S. oil prices made small gains in topsy-turvy trading that had briefly sent the market to nearly a six-year low Thursday.

Bottom-pickers and sellers concerned about oversupply battled for control of a market that has fallen about 60% in six months. Private data suggested that a glut of oil kept growing in recent days, triggering Thursday’s selling, but that simply drew in the type of traders who keep waiting for oil to turnaround, traders said.

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