We all know the retail industry is struggling.

But some retailers are staying strong while others suffer—Morgan Stanley recently finished a study that looked into which retailers are sinking and which are swimming. It considered 11 factors over the past decade, including protection from what Morgan Stanley calls the “Amazon threat” as well as growth in comparable sales, Business Insider reports.

See which four stores are thriving.

1. Ross Stores

Discount stores are booming, and Ross Stores (ROST) more than most.

Neil Saunders, CEO of the Conlumino consulting firm, wrote recently in a note to his clients:

"Ross has benefited from the continued appetite of American consumers to bargain hunt and look for offers and deals in a bid to make their dollar stretch further. That trend shows no sign of dissipating; indeed, it strengthened into the final quarter of last year, something that was undoubtedly helpful to Ross."

2. TJ Maxx

TJ Maxx (TJX) is all about bargain hunting—and it's working, comparable sales were up 5% at the end of fiscal 2016.

According to BuzzFeed News, its sales have even surpassed those of Macy's, and Quartz's Chase Purdy says the store is flourishing in part because "nobody has figured out how to sell off-price clothing very well on the Internet."

3. Lululemon

Lululemon (LULU) has accomplished what most companies can only dream of—it has convinced women to pay a premium and avoided the retail trend of incessant discounting. In addition, the store sells a lifestyle and an experience, not just yoga clothes.

4. L Brands

L Brand's (LB) Victoria's Secret dominates the lingerie sector by a crushing 61.8%, according to IBISWorld. Victoria's Secret stores took in $6.1B in sales in 2015.

L Brands also runs the successful Bath & Body Works—the store that capitalized on Millennials' love for nostalgia by offering iconic, older fragrances. [BI]