NEW YORK (Reuters) - Citigroup Inc <C.N> CEO Mike Corbat said the deal the bank made with Costco Wholesale Corp <COST.O> to replace American Express Co <AXP.N> as the issuer of credit cards for the retailer will be profitable for his shareholders.

Responding to speculation in the card industry that Citigroup gave too much to Costco in negotiations earlier, Corbat said the deal is "without a doubt accretive" to shareholders and would be even if Citigroup did not have deferred tax assets it can use to shelter income from taxes.

Corbat, speaking at an investor conference in New York, also said second-quarter revenue from capital markets trading is "very similar" so far to the same period a year earlier.

(Reporting by David Henry in New York)