American International Group (AIG) has reached an adverse development reinsurance agreement with the Berkshire Hathaway unit National Indemnity Company (NICO), which has become effective on January 1, 2016. AIG has revealed that the agreement facilitates coverage of 80% of significantly all of its US Commercial long-tail exposures for accident years up to 2015, comprising the biggest part of AIGs casualty exposures in the US market during the said period. AIG, adhering to the terms of the deal, will maintain exclusive right to manage and resolve claims, while NICO enjoys a range of access, association and consultation rights.