Why the Same Business Can Report Very Different Numbers
Stack two companies' margins side by side and the higher one looks like the better business, until you discover the difference is entirely an accounting choice rather than anything happening in the real economics of either company. Comparability problems are the reason ratio comparisons across companies require more care than a simple side-by-side lookup.
Where comparability breaks down
Accounting standards permit real, legitimate flexibility in how companies record economically identical events, a flexibility that exists because a single rigid rule cannot fairly capture every industry's genuinely different economics, and that flexibility is the single biggest source of misleading side-by-side comparisons. Inventory costing is the clearest example: under FIFO (first in, first out), a company assumes it sells its oldest, typically cheapest, inventory first, while under LIFO (last in, first out), permitted in the United States but not under international accounting standards, a company assumes it sells its newest, typically priciest, inventory first. During a period of rising prices, these two methods produce meaningfully different cost of goods sold, and therefore different gross margin and net income, for two companies selling the identical physical product at the identical price.
Depreciation is a second, equally consequential source of distortion. Two companies buying identical equipment can choose different useful life assumptions, straight-line versus accelerated methods, and different salvage value estimates, all of which are defensible judgment calls within accounting rules but which shift how much expense hits the income statement in any given year without changing the underlying cash spent on the equipment. A third source is the treatment of leases, research and development, and other costs that some companies capitalize (spread onto the balance sheet and expensed gradually) while others expense immediately, along with the ever-present issue of one-time or non-recurring charges that some companies strip out of their own preferred "adjusted" earnings figures and others do not. Finally, companies reporting under different accounting frameworks, U.S. domestic standards versus the international standards most non-U.S. companies use, differ in specific, material ways on inventory costing, development cost capitalization, and asset revaluation, meaning a raw cross-border comparison of two companies' statements is rarely apples to apples without adjustment.
A further, more subtle comparability problem arises from how companies define and report their own preferred non-GAAP or adjusted metrics, figures like adjusted earnings, adjusted EBITDA, or free cash flow as management chooses to define it, which appear prominently in earnings releases and investor presentations alongside the officially audited figures. Two companies in the same industry can each report an "adjusted" profit metric that excludes a different set of expenses, one excluding stock-based compensation and restructuring charges, another excluding those plus acquisition-related amortization and litigation costs, and a side-by-side comparison of the two adjusted figures compares not the businesses but the breadth of each management team's own exclusions, a distinction easy to lose sight of when both figures are presented with equal prominence and equal confidence in a press release.
Two worked examples
Consider two identical retailers, each buying 1,000 units early in the year at $10 apiece and another 1,000 units later in the year at $14 apiece, as prices rise, then each selling exactly 1,000 units for $20,000 of revenue. Retailer A uses FIFO and is assumed to have sold its earlier, cheaper units first: cost of goods sold = 1,000 × $10 = $10,000, giving gross profit of $20,000 − $10,000 = $10,000, a 50% gross margin, with the pricier $14 units still sitting in ending inventory at $14,000. Retailer B uses LIFO and is assumed to have sold its later, pricier units first: cost of goods sold = 1,000 × $14 = $14,000, giving gross profit of $20,000 − $14,000 = $6,000, a 30% gross margin, with the cheaper $10 units remaining in inventory at $10,000. Both retailers ran the identical business, bought the identical units, and sold the identical volume at the identical price; the 20 percentage point gap in reported gross margin is entirely a function of accounting policy, not operating performance.
The second example shows how depreciation assumptions distort reported profitability. Two firms each buy $1,000,000 of identical manufacturing equipment. Firm C depreciates it straight-line over a 10-year assumed useful life: annual depreciation = $1,000,000 ÷ 10 = $100,000 per year. Firm D depreciates the same class of equipment straight-line over a 20-year assumed useful life: annual depreciation = $1,000,000 ÷ 20 = $50,000 per year. All else equal, Firm D reports $50,000 more pretax income every year than Firm C, purely because of a longer useful life assumption, inflating its apparent margins and its return on assets relative to Firm C even though both firms spent the identical amount of cash on identical equipment and neither one is more efficient than the other in any real sense.
Combining the two distortions shows how quickly they compound. If Firm C also happens to use LIFO while Firm D uses FIFO, and both are operating in the same inflationary environment as the retailer example above, the two accounting choices stack: Firm D's longer depreciation schedule inflates its reported income relative to Firm C's, and its FIFO inventory accounting inflates it further still relative to Firm C's LIFO figures, potentially producing a combined reported margin gap of well over twenty percentage points between two businesses that are, in every operational respect, identical. An investor unaware of either policy difference, let alone both stacked together, could conclude Firm D is a dramatically superior business when the entire gap is attributable to two legitimate, fully disclosed accounting choices.
What the evidence shows
Accounting research comparing companies before and after mandated accounting standard changes has repeatedly documented sharp, purely mechanical shifts in reported margins, leverage ratios, and returns on assets that had no connection to any actual change in the underlying business. A widely studied case is the shift requiring companies to bring most operating leases onto the balance sheet rather than disclosing them only in footnotes: firms with large lease footprints, notably retailers and airlines, saw reported assets and liabilities jump substantially overnight, mechanically moving their leverage and asset turnover ratios even though not a single lease contract or operating decision actually changed. Researchers use these natural experiments precisely because they isolate the effect of accounting policy from real economic performance, and the magnitude of the ratio shifts observed, often large enough to flip a company from looking like an industry's most conservative balance sheet to among its more leveraged ones, illustrates how much comparability problems can matter in practice.
Cross-country accounting research comparing firms reporting under different frameworks has similarly found that raw, unadjusted profitability and valuation multiples differ systematically and persistently between reporting regimes in ways that reflect accounting rules rather than economic performance, which is why professional cross-border equity analysts routinely rebuild key figures onto a common accounting basis before comparing valuation multiples for companies domiciled in different countries.
Research specifically examining companies' own non-GAAP adjusted earnings disclosures has found that the gap between adjusted and officially reported figures has, on average, widened over time as more companies adopt more expansive exclusion lists, and that firms with unusually large or unusually inconsistent gaps between their adjusted and reported earnings have, on average, shown weaker subsequent stock performance than firms whose adjusted figures stay closer to their audited results. This does not mean every adjustment is a red flag; genuinely one-time items do occur and excluding them can produce a more representative picture of ongoing operations. It does mean the size and consistency of the gap itself carries information worth tracking over time rather than accepting at face value each quarter, and that tracking is only possible because the officially reported figures remain available alongside the adjusted ones in every filing, a comparison point worth returning to each time a new quarter's adjusted figure is announced.
Applying it in a real portfolio
Before comparing two companies' margins, ROE, or valuation multiples directly, check three things in the footnotes: the inventory costing method (FIFO versus LIFO, disclosed in the accounting policies note, along with a LIFO reserve figure that lets you approximately convert a LIFO company's numbers to a FIFO-equivalent basis), the depreciation method and typical useful life assumptions by asset category, and whether either company has recently reported significant one-time charges or gains that management excludes from its own adjusted earnings figures. This ten-to-fifteen minute check before any side-by-side comparison catches the majority of comparability distortions that would otherwise lead an investor to conclude one company is a meaningfully better or cheaper business than another when the gap is substantially, or entirely, an artifact of accounting policy rather than operating reality.
This discipline matters most precisely in the situations where it is most tempting to skip it, when a quick screen has already surfaced a company that looks unusually cheap or unusually profitable relative to a named peer. The stronger the apparent gap, the more valuable the ten-minute footnote check becomes, since a genuinely large mispricing and a purely accounting-driven illusion look identical from the ratio table alone and only diverge once the underlying policies are compared line by line.
Actionable breakdown
- Checking inventory accounting
- Note whether each company uses FIFO or LIFO.
- Use the LIFO reserve to approximate a FIFO-equivalent figure.
- Expect larger gaps during periods of rapid inflation.
- Checking depreciation and capitalization
- Compare useful life assumptions by asset category.
- Check whether R&D or software costs are capitalized or expensed.
- Note any recent lease accounting changes affecting the balance sheet.
- Checking one-time items and framework
- Strip out disclosed one-time charges before comparing net income.
- Note the accounting framework each company reports under.
- Flag any recent acquisition inflating the reported asset base.
- Checking adjusted metrics
- List exactly what each company excludes from adjusted earnings.
- Track the size of the gap to reported earnings over time.
- Question a widening or unusually large adjustment gap.
Common pitfalls
Comparing margins without checking inventory method: a FIFO versus LIFO gap can swing reported gross margin by twenty percentage points or more during inflationary periods on an identical business.
Ignoring depreciation assumptions: a longer assumed useful life mechanically inflates reported profit and asset returns without any real efficiency gain.
Treating adjusted earnings figures as neutral: companies choose which items to exclude from their own adjusted metrics, and those choices are rarely consistent across companies or across time within the same company, which is exactly why the size of the adjustment itself deserves tracking rather than being treated as a fixed, comparable baseline.
Comparing across accounting frameworks without adjustment: raw multiples for a domestic filer and a foreign filer under a different framework are rarely directly comparable without restating one onto the other's basis.
Accepting each company's own adjusted metrics at face value: two firms' self-defined adjusted earnings figures can exclude very different sets of costs, making the comparison arbitrary rather than meaningful.
The bottom line
Before trusting a side-by-side comparison of two companies' ratios, check whether the gap reflects genuinely different businesses or simply different, equally legitimate, accounting choices stacked on top of one another.
Ratio analysis · Profitability measures · A full worked illustration · Value investing: the Graham technique · Reading financial statements