BP plc on Monday formally laid the groundwork to launch its U.S. oil and natural gas pipeline assets as a separate company.

Indirect subsidiary BP Midstream Partners LP filed a Form S-1 with the U.S. Securities and Exchange Commission (SEC) related to the proposed initial public offering (IPO) of common units representing limited partner interests.

The London-based super major in July said it would begin evaluating whether to IPO a master limited partnership (MLP) to support and build its midstream business. As envisioned, the MLP would be launched on the New York Stock Exchange under “BPMP” by the end of the year, depending on market conditions.

BP Midstream Partners was formed to own, operate, develop and acquire pipelines and other midstream assets. If the IPO is completed, BP would own the general partner, all of its incentive distribution rights and most of the limited partner interests.

The new company is to be headquartered in Houston, with offices in Chicago.

Initially, the assets would consist of stakes in one onshore crude oil pipeline system, one onshore refined products pipeline system and one onshore diluent pipeline system, which carry shipments to or from BP’s Whiting Refinery in Indiana.

The MLP also would hold interests in four offshore crude oil pipeline systems and one offshore natural gas pipeline system that connect production areas in the Gulf of Mexico (GOM) with the Gulf Coast refining and distribution hubs.

BP did not disclose which systems initially would be included in the spinoff. It operates some of its pipelines and holds stakes in several others. BP Pipelines (North America) transports more than 1.3 million b/d of oil, refined products and natural gas through nearly 3,500 miles of pipeline.

Now headquartered in Chicago, BP’s pipeline operations are managed from control centers in Oklahoma and Washington. BP also holds an interest in multiple joint ventures, some of which are operated by third parties.

Citigroup, Goldman Sachs and Morgan Stanley are acting as book-running managers and Citigroup is the structuring agent for the proposed offering.

Three years ago Royal Dutch Shell plc launched its midstream subsidiary on the New York Stock Exchange as an MLP, initially to hold GOM crude oil pipelines. The deal in 2014 sought $785 million but raised $920 million in its debut. Today Shell Midstream Partners LP is estimated to be worth more than $4 billion.

“We don’t see this as a needle mover for BP the same way as it is for Shell, where we see $30 billion of value that Shell has in its U.S. infrastructure assets,” said Tudor, Pickering, Holt & Co. BP’s midstream properties, if they are worth an estimated $2.1 billion of which 25% is debt, “leaves around $1.6 billion of equity value.”