????Treasury unveils plans to police this fast-growing -- but unregulated -- corner of the markets that many believe contributed to the financial crisis.

????By Colin Barr

????Treasury Secretary Tim Geithner set plans Wednesday to rein in the wild and wooly derivatives markets.

????Geithner proposed requiring that over-the-counter derivatives such as credit default swaps be traded on exchanges, and that all major dealers in derivatives markets be subject to federal oversight.

????Geithner said the rules would bolster the stability of financial markets, promote efficient and transparent pricing and help regulators stamp out fraud and abuse.

????Appearing at a press conference in Washington, Geithner said he expects to propose the new framework to Congress in coming weeks as the administration and legislators hash out new laws governing derivatives markets.

????"The financial crisis was caused by -- and exposed - significant gaps in oversight," he said. "We are committed to working with Congress to create more comprehensive system."

????The proposal comes as the administration struggles with an economic downturn that has been deepened by last fall's near collapse of the financial sector. Simply put, derivatives are types of securities that derive their value from another asset, such as a stock, bond or currency.

????Many large financial firms had made outsized bets on certain types of derivatives during the past few years. When credit markets were functioning normally, many users profited handsomely, seemingly with little risk. But last fall's collapse of Lehman Brothers changed all that.

????Geithner said that while derivatives weren't the cause of that plunge, their untrammeled growth over the past decade and poor disclosure surrounding their use made the financial system more vulnerable to panics.