Earlier this year, Walmart pledged to increase its starting wages, affecting about 40% of its workforce, but some employees who’ve been with the company for years and may not be affected by the pay hikes aren’t thrilled.

The wage increases mean that new and recent hires will be earning more. for example, new cashiers are seeing their starting pay go from at least $7.65/hour to $9/hour with the intention of reaching $10/hour by 2016. Newly hired managers, who currently start at $13/hour, will start being paid $15/hour.

But that leaves some longtime employees who already make more than the company minimum out in the cold.

It’s apparently not much different than when you see the cable or phone company you’ve been with for years giving away all sorts of perks, but only to new customers.

One 10-year Walmart worker in Illinois tells Bloomberg that there is growing discontent among workers who see new employees getting raises while their pay remains the same.

“It is pitting people against each other,” she explains. “It hurts morale when people feel like they aren’t being appreciated.”

She says her colleagues now talk daily about looking for work elsewhere.

Walmart acknowledges that it expected some blowback when it announced that less than half the workforce would be getting raises.

The company tells Bloomberg that it’s trying to retain these more veteran employees by giving them more desirable hours and offering training programs to help them advance in their careers.

“We are constantly looking and evolving what the right pay should be and we were aware of the issue,” the company’s head of human resources for U.S. stores explains. “We weren’t prepared to go forward with any additional increases but have continued to look at it to see if there is something else we should do for those in the middle.”

Economists say Walmart may be risking the ire of its workers by doling out raises on such a large scale, and without respect to an employee’s merit.

“Workers appear to pay attention to peer wages,” Laura Giuliano, an associate professor of economics at the University of Miami, tells Bloomberg. “Even a small difference can matter, and whether or not it is going to matter may well depend on whether it appears arbitrary or unfair.”

Likewise, David Cooper, an economic analyst at the Economic Policy Institute, says that if a company is going to bring up the bottom of its pay scale, it follows that you should bring up the middle-earners as well in order to maintain the existing wage hierarchy. Otherwise, “folks are going to leave or start complaining more vocally.”

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