Over the past three years, no innovation has captivated the attention of investors quite like the rise of artificial intelligence (AI). However, this is far from the only trend that's helped lift Wall Street's major stock indexes to new heights.

Enthusiasm surrounding stock splits in some of the market's most-influential businesses is another catalyst responsible for boosting equity valuations.

A stock split is an event that allows a publicly traded company to cosmetically adjust its share price and outstanding share count by the same magnitude. These changes are entirely surface-scratching in the sense that they don't affect a company's market cap or in any way influence its underlying operating performance.

An up-close view of the word, Shares, on a paper stock certificate for a publicly traded company.

Image source: Getty Images.

But even though stock splits are surface-scratching in nature, there's a wide variance in investor opinion when it comes to the type of split being enacted. For instance, the investing community usually shuns reverse splits. This type of split, which is designed to increase a company's share price, is often undertaken by struggling businesses that are attempting to avoid delisting from a major U.S. stock exchange.

Comparatively, investors are usually excited to put their money to work in companies announcing and completing forward splits. This variety of split is used to make a company's shares more nominally affordable for everyday investors who can't buy fractional shares through their broker. Most of the businesses completing forward splits have well-defined competitive advantages and are innovative leaders within their respective industries.

Thus far in 2025, three prominent companies have announced and completed forward splits, perhaps none of which has made waves more than auto parts chain O'Reilly Automotive (ORLY -0.14%). But with chief rival AutoZone (AZO -0.62%) topping $4,000 per share for the first time in its storied history, the question has to be asked: Is it about to become Wall Street's next stock-split stock?

O'Reilly Automotive kicked off stock-split euphoria in 2025

Following a year where AI stocks dominated the forward-split landscape, 2025 has been all about prominent non-tech companies like O'Reilly Automotive. Although it wasn't the first high-profile stock to complete a split this year -- it allowed its shareholders to vote on the stock-split proposal at its annual shareholder meeting in May -- O'Reilly was the first to announce its intent to complete a 15-for-1 forward split in mid-March.

The catalyst for O'Reilly's largest-ever forward split is simple: Its stock has gained approximately 65,000% since its initial public offering (IPO) in 1993. Had O'Reilly not split, its share price would be north of $1,565, based on its closing price on Aug. 6.

O'Reilly Automotive's decades of outperformance boils down to a combination of factors.

To begin with, Americans are hanging onto their cars and light trucks for longer than ever before. A new report from S&P Global Mobility finds the average age of cars and light trucks on U.S. roadways jumped to an all-time high of 12.8 years in 2025, up from 11.1 years in 2012. Rising interest rates on auto loans, coupled with President Trump's tariffs on foreign auto imports, means drivers and mechanics will be relying on auto parts chains like O'Reilly to keep their existing vehicles running well.

Second, O'Reilly Automotive refined its distribution network with its hub-and-spoke model. It closed out 2024 with 31 regional distribution centers surrounding by close to 400 hub stores and more than 6,000 retail locations. According to the company, these hub stores can feed retail outlets more than 153,000 stock-keeping units (SKUs) on a same-day or overnight basis.

The final piece of the puzzle for O'Reilly has been its sensational share repurchase program, which kicked off in January 2011. The company has spent about $26.6 billion to buy back just shy of 60% of its outstanding shares in under 15 years. For businesses with steadily growing net income, buybacks have a tendency to boost earnings per share (EPS) and can make a company's stock more attractive.

A person holding and closely examining a jug of motor oil in a retail store.

Image source: Getty Images.

Is AutoZone Wall Street's next stock-split stock?

Since AutoZone went public on April 1, 1991, its shares have climbed by more than 14,000%! Despite this outperformance, the company has completed only two forward splits:

  • February 1992: 2-for-1
  • April 1994: 2-for-1

More than 31 years removed from its last split, AutoZone stock now tips the scales at north of $4,000 per share.

The same macro factors propelling growth in O'Reilly Automotive are working in AutoZone's favor. People keeping their cars longer than ever before translates into mechanics and drivers turning to prominent auto parts chains for the parts and accessories needed to keep their vehicles in good running order.

Similarly, AutoZone offers a distribution network that's helping to meet the needs of its customers. It's aiming to build more than 200 megahubs, which are stores that can carry up to 110,000 SKUs. These megahubs act similar to O'Reilly's hub stores in that they're designed to rapidly replenish inventory or meet the needs of customers in satellite retail stores.

But the biggest differentiator, from an investment standpoint, between AutoZone and O'Reilly Automotive is their share-repurchase programs. AutoZone kicked off its buyback program in fiscal 1998 (its fiscal year ends on the last Saturday of August) and has spent approximately $38.1 billion over that span buying back 155.5 million shares. In total, the company has retired a jaw-dropping 90.3% of its outstanding shares, which has had an undeniably positive impact on its EPS.

While all of these foundational factors suggest that AutoZone stock will climb over the long term, a high share price alone isn't enough to warrant a stock split.

Normally, a company's board will push for a stock split when the nominal share price becomes burdensome for retail investors. But the rise of fractional-share investing with online brokers has reduced the urgency for some companies to conduct stock splits.

Furthermore, the composition of a company's shareholders comes into play. If an overwhelming percentage of shares are held by institutional investors, there's not much of a catalyst for a stock split. Fund managers aren't in need of a lower nominal share price. Only 9.4% of AutoZone's shares are held by non-institutional investors, which is a low figure.

Given a lack of retail investor ownership, it doesn't seem likely that AutoZone will join its chief rival as Wall Street's next stock-split stock.