The tentative approval of Visa Inc. and MasterCard Inc.'s proposed $7.25 billion settlement of a merchant fee price-fixing case will be challenged in a federal appeals court, according to a notice filed by objecting plaintiffs, Bloomberg News reported yesterday. Four retailers and six trade groups today filed the notice that they are appealing a component of U.S. District Judge John Gleeson's approval order barring merchants from suing the payment firms over the fees. Nearly 1,200 retailers and trade organizations opposed the accord, which would end seven years of litigation over interchange, or swipe, fees that retailers are charged when customers pay with credit cards. Lawyers for the objectors argued at a Nov. 10 hearing that the agreement is unfair because it strips merchants of the right to sue over the fees in the future.