ONEOK Partners LP (NYSE: OKS) opened a public offering of 11 million common units that represented limited partner interests, the company said May 12.

Net proceeds will support general partnership purposes and also will repay outstanding amounts under the commercial paper program, ONEOK Partners added.

An underwriters’ monthlong option to purchase an additional 1.65 million units might be granted, the company said. ONEOK will have 244.1 million units outstanding after the offer closes, the company said. This amount will include 171.1 common units and 73 million class B units, the company noted. Between ONEOK Partners and its subsidiary—the sole general partner—the aggregate ownership interest will be about 39.3%, the company added.

BofA Merrill Lynch, Barclays, Morgan Stanley (NYSE: MS), UBS Investment Bank, Wells Fargo Securities LLC, Citigroup Inc. (NYSE: C), Deutsche Bank Securities Inc., Goldman, Sachs & Co. (NYSE: GS), J.P. Morgan and

RBC Capital Markets are joint book-running managers, ONEOK Partners said.

Tulsa, Oklahoma-based ONEOK Partners LP is an MLP that focuses on domestic natural gas and NGL.