Is AZO Stock a Good Investment? AutoZone Earnings, Valuation and Key Risks

AutoZone reported fourth-quarter fiscal 2026 results before the US open on 22 September 2026, and the headline was a good one: diluted earnings per share of $56.05, up 15.1% from $48.71 a year earlier, on net sales of $6.59bn. The shares rose about 6% on the day to close near $2,982, having ended the previous session at a fresh 52-week low of about $2,805. Full-year sales came in at $20.34bn with diluted EPS of $152.55.

The question in the headline deserves a straight framing rather than a verdict, and the numbers give an unusually clean one. AutoZone produced 15.1% earnings growth out of domestic same-store sales of just 1.6%. Almost none of that gap was demand. Gross margin expanded 182 basis points to 53.3% — but 145 basis points of that came from tariff refunds and a further 105 basis points from a non-cash LIFO swing, with commercial mix working against it. What you are actually being asked to judge is how much of a large earnings beat survives once two non-operational items and a shrinking share count are taken out of it.

What AutoZone reported

The quarter covers the 16 weeks to 29 August 2026. Net sales of $6.59bn were up 5.6% year on year and fell short of a consensus that sat near $6.7bn. Earnings per share beat consensus, though published estimates for the quarter differ enough between data providers that the size of the beat is not worth quoting precisely. Total company same-store sales rose 1.5%, domestic same-store sales 1.6%, and international same-store sales 1.3% on a constant-currency basis.

Operating profit rose 10.1% to about $1.32bn. That equates to an operating margin just under 20% — 19.9% on the reported gross margin and operating expense ratios — against roughly 19.1% a year earlier, an expansion of around 81 basis points.

The composition of that expansion is the whole story. Gross profit was 53.3% of sales, up 182 basis points. AutoZone attributed the increase to a 145 basis point impact from tariff refunds — a $96m item — and a 105 basis point net non-cash LIFO impact, partially offset by higher commercial mix. The LIFO line alone swung from an $80m charge in the prior-year quarter to a $15m charge in this one. Those two items together are worth 250 basis points; the gross margin moved 182. Absent them, the underlying gross margin went backwards.

Operating expenses, meanwhile, deteriorated. They rose to 33.4% of sales from 32.4%, a full percentage point of deleverage that the company attributed primarily to growth initiatives. That is not a cost-control failure so much as the arithmetic of opening stores faster than sales are growing.

And AutoZone did open stores fast. The company added 175 in the quarter and 374 across fiscal 2026 — the most in a single fiscal year in its history — ending with 8,031 stores, including its 1,000th in Mexico. It finished the year with 172 Mega Hubs after opening 39 during the year. Domestic commercial sales, the do-it-for-me business sold to professional garages, reached $1.9bn in the quarter, up 8.6%, and grew close to 11% across the full year, helped by better inventory availability and the Mega Hub build-out.

On capital returns, AutoZone repurchased $697.5m of stock in the quarter. Operating profit grew 10.1% while EPS grew 15.1%; the roughly five-point gap between those two figures is essentially the buyback, working on a share count that is among the smallest of any large US retailer.

Why the market reacted the way it did

A 6% rally on a revenue miss looks odd until you look at where the stock was standing. AutoZone had made a fresh 52-week low as recently as 21 September, closing that session at about $2,805 and well down from a 52-week high of $4,332.68, and had fallen after three of its previous four earnings reports. The market went into the print positioned for another disappointment, with analysts trimming targets in the run-up. Against that, an EPS beat and visible margin expansion were enough.

The more substantive reason is commercial. Domestic commercial sales up 8.6% in the quarter and around 11% for the year is the one line in the release that is unambiguously operational, unambiguously accelerating, and unambiguously the part of the business AutoZone has been investing to win. The DIY consumer remains soft — 1.6% domestic comps in a business with pricing power tells you volumes are flat at best. But do-it-for-me is a structurally larger addressable market, and the Mega Hub network is the mechanism for taking share in it. Management pointed to sales improving late in the quarter and guided to growth in fiscal 2027.

What the market arguably under-weighted on the day is the quality of the margin. Several write-ups of the print led with the tariff refund and LIFO contribution rather than the headline beat, and they were right to. Both items are real cash or real accounting, but neither tells you anything about whether AutoZone can earn a higher margin next year. A 145 basis point tariff refund is a recovery of costs previously incurred; a favourable LIFO swing reflects the rate of inflation in inventory cost, not commercial execution. Strip them and the picture is a business whose gross margin is under pressure from commercial mix while its cost base deleverages on aggressive store growth.

The Openbook read: where this leaves the five factors

Momentum improves from a very low base and remains the weakest factor. The stock spent the summer setting 52-week lows and sits roughly a third below its high; one 6% session does not reverse that. What has changed is the shape of the news flow — this is the first print in a while that did not trigger a decline, and the late-quarter sales improvement management flagged gives the next quarter something to build on.

Growth is the factor that should trouble anyone using this print as a bull case. Domestic comps of 1.6% and international comps of 1.3% describe a business whose existing store base is barely growing. Total sales growth of 5.6% is therefore overwhelmingly a function of the 374 new stores. That is real growth, but it is bought growth: it consumes capital, it deleverages operating expenses, and it does not indicate underlying demand. The commercial line at +8.6% is the genuine growth asset here and it is doing well; the DIY half is not.

Profitability is where the headline flatters and the detail does not. On reported numbers the factor improves — 81 basis points of operating margin expansion is meaningful. On underlying numbers it deteriorates: 250 basis points of one-off and non-cash gross margin help produced 182 basis points of actual expansion, which means the operating business gave ground, and operating expenses simultaneously worsened by 100 basis points. This is the single most important correction to make when reading the quarter. A margin that improves because of a tariff refund is not the same asset as a margin that improves because of mix or pricing, and conflating the two is how a good quarter gets mistaken for a turning point.

Solvency is unchanged and is the factor AutoZone has always run differently from its peers. The company operates with negative shareholders' equity by design, funding an enormous buyback programme with debt and supplier financing, and the $697.5m repurchased in a single quarter is consistent with that long-standing approach rather than a change in it. It is a structure that works while cash generation is stable and becomes a constraint if it is not — which makes the commercial trajectory, not the balance sheet itself, the thing that governs this factor.

Reward/Risk is the most interesting factor after this print, because the two sides have moved in opposite directions. The reward case strengthened: commercial is compounding at close to 11%, the Mega Hub build is producing the availability that wins professional accounts, and the stock is a third off its high. The risk case also strengthened: the reported margin expansion is substantially non-repeatable, operating expenses are deleveraging, and the record store-opening programme means fixed costs are rising into a period of roughly flat comparable demand. The honest summary is that the range of outcomes widened rather than narrowed. Screening AutoZone against other US specialty retailers on our screener is the sensible way to frame where that range sits relative to the sector.

The read-across

The clearest implication is for the rest of the US auto aftermarket, where the same DIY-versus-DIFM divergence applies. AutoZone's numbers say professional demand is healthy and consumer self-service demand is not, and that split favours competitors weighted toward the commercial channel — notably O'Reilly Automotive, whose business mix leans further that way — over those more exposed to the retail customer. Any read on Advance Auto Parts should be taken from the commercial line rather than the headline comp.

Beyond the sector, the tariff refund is the detail with the widest application. A $96m recovery worth 145 basis points of gross margin in a single quarter is a reminder that tariff costs booked through inventory in prior periods are now being recovered in some cases, and that this creates a temporary, non-recurring uplift in reported gross margins across import-heavy retailers. Anyone comparing retail margins year on year this reporting season needs to check whether a tariff item sits inside the comparison before drawing a conclusion about operating performance.

The LIFO swing carries a similar warning. A move from an $80m charge to a $15m charge is a function of decelerating inventory cost inflation, which is a macro condition rather than a company achievement, and it will affect any US retailer on LIFO accounting in the same direction at roughly the same time.

What to watch next

The first quarter of fiscal 2027 covers the 12 weeks to late November and typically reports in December. The specific things to watch are, in order: whether domestic commercial sales growth holds near the 8.6% posted in the fourth quarter, because that is the load-bearing number in the entire investment case; whether domestic comparable sales move above the 1.6% level, which would indicate the DIY consumer is stabilising; and what gross margin does once the tariff refund and the favourable LIFO comparison are absent, since that is the first clean look at underlying profitability in several quarters.

Also watch the operating expense ratio. At 33.4% of sales against 32.4%, the deleverage from the record store programme is running at a full point, and the pace of new openings in fiscal 2027 determines whether that continues. Finally, watch the buyback run rate. At $697.5m in a quarter it is doing a great deal of the work in the EPS line, and any slowdown would expose how modest the underlying profit growth actually is.