JPMorgan, Deutsche Bank
JPMorgan was willing to pay a higher price for the business, sources said, although details of the likely purchase price were not immediately known. One source said RBS was also keen for a quick transaction and due diligence process.
RBS Sempra is 51 percent owned by Royal Bank of Scotland
RBS, JPMorgan and Deutsche Bank declined to comment and RBS Sempra could not immediately be reached.
RBS Sempra trades commodities ranging from oil and natural gas to metals and agricultural products and would add to JPMorgan's existing commodities business to challenge market leaders Goldman Sachs
New York-based JPMorgan has picked up assets and market share after weathering the financial crisis better than most rivals. It last week reported a fourth-quarter profit of $3.3 billion, fueled by strong investment banking.
RBS Sempra was formed in 2008 when RBS bought its controlling stake for $1.7 billion and California utility Sempra Energy invested $1.6 billion.
RBS Sempra, whose antecedents include such colorful names as Enron and Metallgesellschaft Ltd, is a big player in the London metals market, while its energy business is largely focused around U.S. utility Sempra Energy.
Much of its business centers around Michael Hutchinson, a towering figure in the closely knit metals community, who stood down as non-executive chairman from RBS Sempra last year, after four decades in the business.
RBS, which is 84 percent owned by the UK government, was given four years by Brussels to sell its stake, but wants to sell it quickly as Chief Executive Stephen Hester is keen for a streamlined RBS to take shape.
RBS Sempra would also lose value if staff leave or uncertainty about the business persisted.
Deutsche Bank said recently it aimed to be among the world's top five commodities firms, from its current position of sixth. But it has said it can achieve this organically, and it has been aggressively investing in the business, including new offices in Houston and Calgary to build out its physical commodities trading to add to its commodities derivatives activity.
(Additional reporting by Philipp Halstrick in Frankfurt, Yan Chong, Jennifer Lan in Singapore and Humeyra Pamuk and Quentin Webb in London; Editing by David Holmes and Sharon Lindores)