He added that their productivity levels are particularly impressive given that they sell their goods at such low prices. According to data from eMarketer, T.J. Maxx and Marshalls pull in about $304 in average sales per foot, while Ross does about $288 in average sales per square foot.
That's much higher than the typical department store. J.C. Penney, for example, averages about $101 in sales per square foot, while Macy's averages about $158, according to the data.
"At their price point ... those productivity levels we view as very, very attractive," Freddo said.
Read MoreRetailers are closing up shop. Here's why...
A recent study by Sterne Agee found that the off-price sector remains highly attractive to female shoppers. The firm, which surveyed more than 1,000 women in the U.S., found that 65 percent of respondents have shopped at an off-price store over the last 12 months, with more than 80 percent of respondents saying they have shopped at either a T.J. Maxx or a Marshalls.
"Notably, customers who are shopping more at off-price (regardless of which concept) most frequently cited Macy's and J.C. Penney as chains where they are shopping less," analyst Ike Boruchow wrote in the report.
On the flip side, among those who are shopping less at off-price stores, Kohl's was the most frequently mentioned beneficiary, he said.
Read MoreStop blaming store size for weak results: DDR CEO
According to Sterne Agee's findings, the most common reason consumers were shopping less frequently at off-price stores was because they're shopping online more. That presents a significant challenge for the off-price retailers, which have a very small presence on the Web.