Senate Democrats agreed Monday to kill a provision from their derivatives bill pushed by Warren Buffett's Berkshire Hathaway Inc., a change one analyst predicted could force the Nebraska company to set aside up to $8 billion.

The Senate Agriculture Committee inserted language into its derivatives bill last week at the request of Sen. Ben Nelson (D., Neb.) that would have exempted any existing derivatives contracts from new collateral requirements -- the money set aside to cover potential losses.