ONEOK announced on Thursday that it has purchased ONEOK Plaza, the 17-story building at 100 West Fifth Street in Tulsa. 

The building currently houses ONEOK's corporate headquarters. 

ONEOK purchased the 517,200-square-foot building for $48 million from Southwestern Associates and RMZ Corp. 

"With this investment, we are reinforcing our strong commitment to Tulsa and downtown," said John W. Gibson, chief executive officer of ONEOK.  "We've been an Oklahoma company for more than a century and a resident at this location since 1984.  We look forward to our continuing role in downtown Tulsa's bright future." 

Completed in 1984, the ONEOK Plaza building is located on the block bordered by Boulder and Cheyenne avenues and Fifth and Sixth streets in downtown Tulsa. 

ONEOK and its predecessor company have been headquartered in Tulsa since 1926 when it moved from Oklahoma City.

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