U.S. Treasury Secretary Timothy Geithner says complex financial instruments called derivatives should be bought and sold with less secrecy and more regulation.

The lightly regulated derivatives market is valued in the trillions of dollars.

Some derivatives were intended as a kind of insurance to reduce the risk of large and complex transactions.  But instead, in some cases, these instruments played a role in the collapse of major financial firms and the start of the current economic crisis.

Late Wednesday, Geithner proposed that derivatives be traded on regulated exchanges and that they be backed by a certain amount of capital in case of default.

The idea must be considered and approved by Congress and the President before it can become law.

Some information for this report was provided by AFP, AP and Reuters.