ConocoPhillips (NYSE: COP) shares gained 5% to $78.14, after the oil company said it would divide into two separate publicly traded companies. Volume for the stock was 17.6 million shares, or better than twice its full-day average volume.

A news release out July 14 noted that ConocoPhillips’ board of directors has approved pursuing the separation of the company’s Refining & Marketing and Exploration & Production businesses into two stand-alone, publicly traded corporations via a tax-free spin of the refining and marketing business to ConocoPhillips shareholders.

As a separate company, the release continues, the Refining and Marketing business of ConocoPhillips will be a leading pure-play independent refiner with a competitive and diverse set of assets. In addition to executing the company’s initiatives to improve downstream returns through portfolio rationalization and other operating efficiencies, the new downstream company will be able to further position its portfolio by pursuing transactions and investments across the value chain.

The release then quoted Conoco CEO Jim Mulva as saying, “Consistent with our strategy to create industry-leading shareholder value, we have concluded that two independent companies focused on their respective industries will be better positioned to pursue their individually focused business strategies.

Mulva concluded, “Both companies will continue to benefit from the size and scale of their significant high-quality asset bases and free cash flow generation, allowing them to invest and create shareholder value in a changing environment.”