O'Reilly Automotive (ORLY -0.46%) operates a fairly boring business selling auto parts to consumers and commercial customers. And yet a $10,000 investment in the retailer at the turn of the century would now be worth over $1.2 million. Could putting $10k into the stock today make you a millionaire?
What does O'Reilly Automotive do?
At its core, O'Reilly Automotive is a retailer. The auto parts it sells place the company into the industrial sector, but the way a retailer grows is basically the same as it would be in any other sector. It can sell more from each of its stores or it can open more stores -- or both. That's really the basic math of growth in the retail niche.

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New stores are far more impactful to top-line growth than selling more from existing stores. That's how O'Reilly has grown so much over the years. To put some numbers on that, it operated 6,416 stores at the end of the first quarter of 2025. Roughly a decade ago, it operated 4,433 locations. Basically, it expanded its store footprint by roughly 45% in 10 years. That's a lot of growth in a fairly short time.
That's not to suggest that O'Reilly isn't operating its stores very well. It couldn't have kept growing like that for so long if it weren't. Notably, in the first quarter of 2025, same-store sales increased a solid 3.6%. Basically, O'Reilly is executing well on the two most important growth drivers it has at its disposal. And that is how it has made millionaires out of early investors.
Future growth will be harder to come by
The problem that new investors have to grapple with is that O'Reilly is a much larger company today than it was a decade ago, let alone at the turn of the century. That makes it harder to keep growing. At some point, it will have saturated the market opportunity it has.
But management doesn't believe it's at that point yet, noting that it has plans to open as many as 210 new stores in 2025. As long as it can keep profitably opening up new locations, the company's growth will likely continue.
That said, there are other issues to consider today. For starters, the company is dealing with rising operating expenses. That led to a year-over-year drop in net income in the first quarter of 2025. Earnings per share rose, but only because of a large share buyback program. Dealing with issues like rising operating costs gets more difficult as a company gets larger because there are more moving parts to deal with.
So O'Reilly is well run, but a more complex business and its massive store count are two issues that may make it a less rewarding investment in the future than it was in the past. Then there's the issue of valuation. The stock's price-to-sales and price-to-earnings ratios are both well above their five-year averages, suggesting it is expensive right now.
That said, the stock has experienced multiple 20%-plus drawdowns since 2000. Such a decline today would make the stock much more attractive, valuation wise. And buying after such a material price drop would increase the chances of it turning a new investor into a millionaire.
Could O'Reilly make you a millionaire?
If O'Reilly can keep growing its business like it has been for years, it could very well help create a few more millionaires along the way. But given its larger size and increased complexity as a business, it could be harder to repeat that feat from here. Which is why valuation is likely to be so important.
If you buy O'Reilly when it is expensive, as it looks today, you materially diminish the chances that it will power your portfolio into the seven-figure space. Given the frequent large drawdowns in the stock, patient investors are probably better off waiting on the shares for now.