Earlier this year, he sold his commodities operation, Marc Rich & Company, to Crown Resources, a unit of a Russian energy trading group.
In the case of JPMorgan, the industry executives familiar with its activities in the RINs market said they were told by a top banker in its commodities operation about the stockpiling.
Until 1999, regulations barred banks from owning nonfinancial companies like commodities operations.
Its fixed income, currency and commodities operations suffered a 34% fall in revenue.
Still, it is unclear if big banks would be required to divest themselves of their commodities operations immediately.
Deutsche Bank, Morgan Stanley and UBS either shuttered or shrank their commodities operations last year this yearr Barclays, Credit Suisse and JPMorgan Chase have scaled back.
The bank's large fixed-income and commodities operations fell 14 percent from the second quarter, while equities fell 15 percent, excluding the accounting gains taken on its debt.
Both will report to Mr. Johansson, who will temporarily lead the fixed income, currencies and commodities operations while UBS seeks a replacement for Andre Esteves.
Last week, in the face of rising regulatory concerns about the big banks' commodities operations, JPMorgan said it was looking to sell its physical commodities businesses, which include sprawling storage and transportation facilities.
The chief executive, Allan E. Moss, said that growth was strong in Asia, Europe and North America and that the investment banking, treasury and commodities divisions had good results, especially in energy and commodities operations in the United States.
Among those scheduled to testify is Saule T. Omarova, a professor at the University of North Carolina at Chapel Hill, who has been critical of bank ownership of commodities operations, and Tim Weiner, an executive at MillerCoors, the big brewing company.
