The shares closed at $85.60 on Wednesday, even as the S&P 500 rose 1.46% and the Dow gained 1.24% in a broadly positive US market session.
It was ONEOK's second straight daily loss, and the stock lagged peers including Atmos Energy, NiSource and UGI, all of which posted smaller declines.
Trading volume reached 5.4 million shares, above the 50-day average of 5.0 million, while the stock finished 10.18% below its 52-week high of $95.30 set on 27 March.
Why did ONEOK's stock plunge despite strong earnings and a raised full-year outlook?
With global energy in turmoil, is ONEOK a key player or a risky bet?