In early May, with its legal options dwindling and investors impatient, BP Plc saw a chance to negotiate what became a US$18.7 billion settlement that ended five years of litigation over the worst offshore oil spill in U.S. history. NEW YORK/LONDON/HOUSTON: In early May, with its legal options dwindling and investors impatient, BP Plc saw a chance to negotiate what became a US$18.7 billion settlement that ended five years of litigation over the worst offshore oil spill in U.S. history.