Whatever the cleanup ultimately costs, BP's partners are on the hook for 35%. So if BP has lost $25 billion in market cap and is only responsible for 65%, then the cleanup must cost almost $40 billion. Hmmm, maybe this is an over reaction by about $38 billion.
The Blow Out Preventer device failed to work properly. That is the responsibility of RIG and Cameron Int'l. The BOP device was 9 years old. Looks like some major liability for RIG and CAM, maybe billions. Plus BP is 12% of RIG's business, so BP can threaten to discontinue business if RIG doesn't step in. Plus, why didn't RIG have an acoustic blowout prevention device on the Horizon?