Which stock exchange did XXX go public on?
SemGroup
SemGroup Corporation's common stock (NYSE: SEMG) was listed on the New York Stock Exchange as of November 11, 2010, and two of its representatives were invited to ring the NYSE opening bell on December 17, 2010, as the company assumed what a Wall Street Journal reporter described as ``a new identity as a conservative middleman to the Midwestern oil and gas industry.''
New York Stock Exchange