It makes perfect sense for investors to seriously consider brand before buying their next stock. What will customers cling to when everything else -- including reason -- goes by the wayside? Why, products with the strongest brands, of course. As entrepreneur Marc Rougier put it, "Brands are the irrational power of our supposedly free and rational world."

With that in mind, today we delve into the wonderful world of gasoline, looking for the strongest brand from industry players like Costco (NASDAQ:COST), Wal-Mart Stores (NYSE:WMT), ExxonMobil (NYSE:XOM), and others.

Costco Gas

Rank and file
We begin by considering data from the 2014 Harris Poll EquiTrend rankings. This is a consumer-based poll that measures brand equity, connection, and buzz. Harris polls 40,000 Americans on aspects such as familiarity, quality, purchase consideration, and a brand's ability to generate conversation online, offline, and across the various social media platforms. The poll's gasoline brand rankings are as follows:






Murphy (Wal-Mart)










Sam's Club







Source: 2014 Harris Poll EquiTrend Rankings.

That's right, Costco is at No. 1. It's almost unfathomable that a company that barely, if at all, advertises for gasoline can take the top spot on this list, but it has. In a way, it's almost an advantage not being an oil company in this case (you'll notice BP is not on the list) and generating good feelings with the larger brand. Cost is obviously a factor as well, as nothing generates brand loyalty like low prices. That's likely why BJ's and the two Wal-Mart brands, Murphy and Sam's Club, also make the list. 

Outside of the retail selections, the rest of the list looks more or less like one would expect. ExxonMobil, Royal Dutch Shell, and Chevron represent big oil and are closely associated with gasoline. It is interesting that Shell places so much higher than its American peers. Part of the explanation is certainly that the company has a large retail footprint, with more than 14,000 gas stations in the United States, more than either ExxonMobil or Chevron. 

Brand matters
Believe it or not, these brand polls are valuable to investors. In 2012, researchers from Georgetown University published an in-depth study to determine whether or not there was a correlation between the perceived value of brand equity and outperformance in the stock market. The researchers tested their hypothesis using data from the financial crisis and determined that not only does brand equity matter, but stronger brand equity correlates to better stock performance, lower volatility, and lower beta. Additionally, consumer-based brand polls like the EquiTrend results we looked at today are a better indicator of brand equity than financially derived brand rankings.

It makes sense then, that brand is something to keep in mind as we continue to build our portfolios. Consider the list above when you're looking for your next investment.

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Aimee Duffy has no position in any stocks mentioned. The Motley Fool recommends Chevron and Costco Wholesale. The Motley Fool owns shares of Costco Wholesale. Try any of our Foolish newsletter services free for 30 days. We Fools may not all hold the same opinions, but we all believe that considering a diverse range of insights makes us better investors. The Motley Fool has a disclosure policy.