At the same time, it downgraded midmarket and bargain retailers like JC Penney (JCP) and Dollar Tree (DLTR). The move follows surprisingly strong reports from the sellers of discretionary items like accessory-maker Fossil (FOSL) and sportswear-maker Lululemon (LULU) -- even while value-oriented companies like Wal-Mart (WMT) have stumbled amid lackluster retail sales.

While stretched consumers are undoubtedly looking for value, analysts say another, subtler dynamic may be in play as well: The sharp stock market rally has lined the pockets of the well-to-do consumers who tend to own more stocks and has given them more discretionary income. At the same time, lower-income shoppers -- sometimes living paycheck to paycheck -- are struggling mightily amid a ravaged job market.

"The sustained rise in the stock market has put more disposable dollars in the hands of upper-end consumers," says Ken Perkins, the President of Retail Metrics. Perkins says his firm has seen business improve at upscale retailers over the last three months. At the same time, "with almost one in five people underemployed, lower- and middle-income consumers just don't have the spending power they used to."

Indeed, shares of pricey retailers like Nordstrom (JWN) and Saks (SKS) are up more than 25% and 15%, respectively, while value-focused companies like Wal-Mart and Ross (ROST) have gained less than 5%.

Tough Road Ahead for Discounters

If a sharp rise in corporate profits follows -- leading to further gains in the stock market -- even as unemployment only slowly recovers, as many predict, this trend could gain strength in the coming year.

To be sure, companies like Nordstrom have introduced lower-price items and now struggle with balancing how to court new customers while maintaining the exclusivity of their brands, Perkins says. But discount retailers may be facing an even tougher road ahead. "The banks are not lending, and consumers can no longer use their homes as piggy banks," Perkins points out. "That will lead to some serious issues."

As the income disparity in the U.S. grows, investors should note that the recession has hammered all consumers -- but it hasn't hit them all to nearly the same degree.