BOSTON, May 8, 2013 /PRNewswire/ -- Block & Leviton LLP ( www.blockesq.com), a Boston-based law firm representing investors nationwide, has commenced an investigation into possible breaches of fiduciary duties by the Board of Directors of Pioneer Southwest Energy Partners L.P. ("Pioneer Southwest" or the "Company") (NYSE: PSE) with regards to the recently proposed going private offer by Pioneer Natural Resources Company ("Pioneer Natural"). Under the terms of the proposal, Pioneer Natural would acquire all of the outstanding, publicly-held Pioneer Southwest common units it does not already own through a stock-for-unit exchange, and Pioneer Southwest will operate as a wholly owned subsidiary of Pioneer Natural. Pioneer Natural currently owns approximately 52.4% of the Company's outstanding units, and it is the sole owner of the Company's general partner. The consideration of 0.2234 of a share of Pioneer Natural common stock for each outstanding publicly-held Pioneer Southwest common unit represents approximately $30.63 at the current trading price of Pioneer Southwest, a paltry premium of just 17%. This acquisition offer appears to have been purposely timed to attempt to siphon away Pioneer Southwest's unrelenting growth from the public shareholders of the Company . Indeed, units of the Company have surged nearly 20% in just the past two months, a larger percentage than the purported 'premium' contemplated in the offer. This prompted Pioneer Natural's attempt to acquire the Company at a discount price and thus harvest its future growth wholly for itself. Block & Leviton's investigation seeks to determine, among other things, whether Pioneer Southwest's acceptance of the offer will represent a breach of their fiduciary duties by failing to maximize shareholder value in the going private transaction and the process by which the Pioneer Southwest Directors ultimately consider and potentially approve the transaction.