If BP walks away from the holdings completely it could write down up to $25 billion, it said.
An Unearthed and HuffPost investigation identified at least eight trade associations the companies failed to disclose in transparency reports.
The people who cleaned up the 200 million-gallon Deepwater Horizon oil spill say they are still dealing with the health and economic fallout.
Eight years later, scientists are confirming the lasting impact of the BP oil spill -- and what may have made it worse.
One of the reports also sheds light on the effect on herring of a 1989 spill in Alaska.
90 companies accounted for 65 percent of worldwide carbon emissions between 1854 and 2013.