(Reuters) - Bank of America Corp <BAC.N> said its businesses and results could be adversely affected and it may have to incur additional costs if Britain's exit from the European Union limits the ability of its UK entities to conduct business in the bloc.

The Brexit vote has introduced "complexities and variables" in calculating fair values of certain businesses, the bank said in a regulatory filing on Monday.

BofA, whose UK exposure is concentrated in multinational corporations and sovereign clients, said net exposure to the UK totaled $56.31 billion as of June 30.

The lender said it now sees legal expenses of up to $1.1 billion beyond accrued liability, down from up to $2.4 billion at March 30.

BofA also said the UK referendum could create "political stress or financial instability" in Italy, Spain, Greece and Portugal. At June 30, net exposure to Spain, Greece and Portugal was $2.6 billion, $261 million and $10 million, respectively.

Citigroup Inc <C.N> said in a filing on Monday that it did not experience any "significant negative impact" on its results or client activity as a result of the Brexit vote.

(Reporting by Nikhil Subba in Bengaluru; Editing by Don Sebastian)