NuStar Energy LP (NYSE: NS) announced on April 12 the pricing of an offering of 12.5 million common units for gross proceeds of about $579 million.

NuStar has granted the underwriters a 30-day option to purchase up to 1.875 million additional common units. In the offering, the partnership expects to sell up to $15 million aggregate purchase price of common units to William E. Greehey, chairman of the board of directors of NuStar GP LLC. The offering is scheduled to close April 18.

NuStar currently intends to use the net proceeds from the offering, including the general partner’s proportionate capital contribution and any exercise of the underwriters’ option to purchase additional units, to fund a portion of the purchase price for the partnership’s previously announced acquisition of Navigator Energy Services LLC and to pay related fees and expenses. Pending such use, the partnership intends to repay borrowings under its revolving credit facility.

UBS Securities LLC is acting as lead book-running manager for the offering and Mizuho Securities USA LLC is acting as a joint book-running manager for the offering. A copy of the prospectus supplement and accompanying base prospectus relating to this offering may be obtained from any of the underwriters, including UBS Securities LLC, 1285 Avenue of the Americas, New York, New York 10019, Attention: Prospectus Dept., Telephone: (888) 827-7275; and Mizuho Securities USA LLC, 320 Park Avenue, 12th Floor, New York, NY 10022, Attention: Equity Capital Markets, Telephone: (212) 205-7600. You may also obtain these documents for free when they are available by visiting the SEC’s website at www.sec.gov.