SemGroup Energy Partners, an LP formed to own, operate and develop a portfolio of midstream energy assets, filed an amended S-1 form with the SEC on Monday. The Tulsa-based company will offer 12.5 million shares at a range of $19-$21 for a proposed market cap of $413 million if priced at the midpoint of the range. Citi and Merrill Lynch are joint bookrunners on the deal.
