Pioneer Natural Resources Company and Pioneer Southwest Energy Partners L.P. Announce $29.20 Pricing of 4.4M Share Public Offering of Common Units

Pioneer Natural Resources Company

and Pioneer Southwest Energy Partners L.P.

today announced the pricing of a public offering of 4,400,000 common units representing limited partner interests in the Partnership at $29.20 per common unit. Gross proceeds to the Partnership from the offering of 2,600,000 primary common units will be $76 million (before underwriting discounts and commissions and offering expenses). The Partnership intends to use the net proceeds from this offering for general partnership purposes, including the acceleration of its 2012 drilling program with the addition of a third drilling rig. The offering is scheduled to close December 16, 2011. In addition to the shares sold by the Partnership, Pioneer, through a wholly-owned subsidiary, sold 1,800,000 common units in the offering, for gross proceeds to Pioneer of $53 million (before underwriting discounts and commissions). The Partnership will not receive any proceeds from the sale of common units by Pioneer. Pioneer has also granted the underwriters a 30-day option to purchase up to an additional 660,000 common units. Pioneer intends to use the proceeds it receives from this offering for general corporate purposes, including funding Pioneer's future capital requirements.