Bentonville-based Wal-Mart will stop accepting signature debit cards issued by MasterCard starting in February. The company is the first major retailer to take such action since a lawsuit settlement freed merchants to pick which credit and debit card services they use. Wal-Mart says MasterCard`s fees for the signature debit cards are too high. It will continue to accept Visa`s signature debit cards. When the change goes into effect February first, Wal-Mart doesn`t expect many customers to be stopped dead at the cash register. Wal-Mart spokeswoman Melissa Berryhill says fewer than one percent of Wal-Mart transactions are under MasterCard signature debit cards, and more than 90 percent of the cards carry a personal identification number that can be used instead of a signature. Wal-Mart will continue to accept MasterCard debit cards if customers key in their PIN numbers. Berryhill said saving money for Wal-Mart customers is at the root of the move.