NEW YORK (MarketWatch) -- Sempra Energy said Monday that Royal Bank of Scotland Group disclosed it may have to sell its majority interest in the RBS Sempra Commodities joint venture, as part of a massive restructuring looming for the U.K. lender.

One of the more profitable components of San Diego-based Sempra Energy's business, RBS Sempra Commodities includes Sempra Energy Trading, RBS Sempra Metals and Sempra Energy Solutions.

Royal Bank of Scotland bought a 51% stake in RBS-Sempra for $1.7 billion in April 2008. Sempra Energy's initial investment in the company was $1.6 billion.

Sempra , best known as the parent of San Diego Gas & Electric as well as Southern California Gas Co., said the company has been informed by Royal Bank of Scotland's management that it may have to divest its interest in RBS Sempra Commodities, under orders from the European Commission.

Sempra said terms of their joint-venture agreement requires that the bank maintain its ownership stake through April 2012.

Any divestiture order, Sempra said, would "allow for an orderly transition, comply with our joint-venture agreement, and be executed in a manner that would maximize the value of the business."

Sempra said it holds "certain rights" regarding any new owners of the RBS stake but didn't specify what the rights were. A phone call to a Sempra spokesperson was not immediately returned on Monday.

"After discussions with RBS, we are confident that RBS is committed to continuing the capital and credit support for the joint venture going forward. Our interests are aligned with RBS in continuing to create value in this business," the company said.

The statement came amid fresh reports that RBS would disclose on Tuesday which assets they will have to sell to satisfy European Union competition concerns, after having received public bailout monen. See full story.

The move by European regulators comes several weeks after Citigroup, itself a recipient of billions in U.S. taxpayer funds, agreed to sell its Phibro LLC unit to Occidental Petroleum Corp. in the midst of questions surrounding the $100 million pay package for Phibro executive Andrew Hall. See full story.

In the second quarter of this year, RBS Sempra Commodities generated $85 million in earnings, accounting for a big chunk of Sempra's roughly $200 million in profit for the period.