Williams Companies Inc. (NYSE: WMB) priced a public offering of 53 million common shares at $57 each, the company said June 17.

A monthlong option to purchase up to nearly 7.9 additional shares was granted to underwriters, the company added.

Net proceeds will finance part of Williams’ acquisition of Access Midstream Partners LP (NYSE: ACMP)—specifically, the 50% general partner interest and 55.1 million limited partner units, Williams said. These units are held by certain funds of Global Infrastructure Partners, a New York-based private-equity firm, the company added.

Citigroup Inc. (NYSE: C), Barclays Plc (NYSE: BCS) and UBS Investment Bank are joint book-running managers, the company said.

Tulsa, Okla.-based Williams Companies Inc. is a North America-focused midstream company.