Even as consumers saved about $80 billion at the gas pump during 2015, it wasn't a very good year for most retailers. Apparel sales were a particularly weak spot, causing revenue to stagnate or decline at many department stores.

Despite these industry trends, top off-price retailer TJX (TJX -2.49%) posted steady sales growth through the first three quarters of its recently ended fiscal year. TJX will report its Q4 earnings on Wednesday. Based on the company's strong track record, there's a good chance it outperformed again last quarter.

Other retailers have fallen flat
Last Thursday, Nordstrom (JWN -0.71%) reported disappointing sales and earnings for its fiscal fourth quarter. This may have been worrisome to some TJX investors because Nordstrom has a significant presence in the off-price sector through its Nordstrom Rack chain.

Nordstrom Rack has posted two straight quarters of declining comp sales. 

Comparable-store sales at Nordstrom Rack declined 3% in Q4. This was the second straight quarterly comp sales decline.

Management admitted that Nordstrom Rack's brick-and-mortar sales fell below the company's plan for most of the past year. However, Nordstrom still claims it gained market share among off-price retailers last quarter, which would be bad news for off-price peers like TJX.

TJX is different
Despite these apparent warning signs, investors shouldn't count TJX out. The company has a remarkable track record of performing well no matter what the retail environment looks like.

This is because TJX has a very flexible business model built around buying merchandise at the last minute, as it sees how consumer trends are playing out. Furthermore, while TJX isn't immune to the pricing pressure affecting the rest of the industry, it has the offsetting benefit of getting great deals on merchandise from vendors that are eager to dump inventory.

TJX is benefiting from full-price retailers' bloated inventories.

Nordstrom Rack has some of the same advantages over traditional department stores. That said, as a "captive" off-price store that exists in part to clear unwanted merchandise from Nordstrom's full-line stores, Nordstrom Rack doesn't have quite as much flexibility in terms of what to order.

Furthermore, weak comp sales figures at Rack stores may be caused in part by cannibalization. Nordstrom has been opening Rack stores at a rapid pace -- it grew the store count by 16% during 2015 -- and investing in off-price e-commerce growth. In fact, Nordstrom's total off-price sales rose 12% during Q4 despite the decline in brick-and-mortar comp sales.

TJX can soar above the industry
TJX's pure off-price business model gives it the tools to succeed even in today's weak retail spending environment. In Q3, it posted 5% comparable-store sales growth. Total sales also grew 5%, despite a 3 percentage point negative impact from the strong dollar.

The strong Q3 performance at TJX came even as comp sales at Nordstrom Rack stores declined 2.2%, demonstrating how the two chains' destinies are not necessarily linked.

Coming into the fourth quarter, while most full-price retailers were swimming in unwanted merchandise, TJX had very lean inventory. As a result, it expected to find great deals from vendors desperate to sell overstocks. This would in turn allow TJX to lure in customers with compelling bargains while maintaining a strong profit margin.

In other words, conditions were ideal for TJX to outperform its peers yet again. I wouldn't recommend betting against this retail juggernaut.