K-Mac, Omni look for buyers.

Byline: Soma Biswas

As new fast-food concepts emerge to appeal to America's changing tastes, two major franchise groups of the nation's more mature brands have put themselves on the selling block for different reasons.

K-MAC Enterprises Inc., one of the three largest Taco Bell franchisees in the nation, and Omni Restaurants Inc., a major Burger King franchise group, are both up for sale, according to investment bankers.

Sources said that K-MAC can fetch as much as $150 million in a sale while Omni is more likely to attract less than $50 million.

That K-MAC is believed to be more valuable isn't surprising, given the recent comeback of Yum! …