What Is Free Cash Flow and Why It Matters More Than Earnings
Earnings per share has a publicist. Every quarter, companies hold earnings calls, analysts revise estimates, and markets move on beats or misses. EPS is the number the financial media is built around.
Free cash flow has no such publicist. It sits quietly in the cash flow statement, three pages after the headline number. Most investors never look at it.
That's a mistake. Of all the measures of business performance, free cash flow is the hardest to fake, the most directly useful for valuation, and the most honest answer to the question every investor should be asking: How much money is this business actually making?
The formula
Free Cash Flow = Operating Cash Flow − Capital Expenditures
That's it. Take the cash the business generates from running its operations, subtract the money it spends maintaining and expanding its productive assets, and what's left is free cash flow. It belongs to the owners.
Operating cash flow starts with net income and adjusts for non-cash items (depreciation, stock-based compensation, changes in working capital). Capital expenditures are the money spent on property, plant, equipment, and other long-lived assets. The difference — FCF — is the cash that could theoretically be returned to shareholders, used to pay down debt, or reinvested at high returns.
You'll find both numbers in the annual 10-K or quarterly 10-Q: operating cash flow in the cash flow statement, capital expenditures typically as a line item in the investing activities section or disclosed in the notes.
Why Buffett prefers it over earnings
Warren Buffett has used the phrase "owner earnings" for decades. His version is a refinement of FCF: net income plus depreciation and amortization, minus the capital expenditures required to maintain competitive position and unit volume. The emphasis on required capex is crucial — Buffett distinguishes between maintenance capex (what you must spend to keep the business where it is) and growth capex (what you choose to spend to make it bigger). Only maintenance capex is a true cost.
The deeper point is philosophical. Reported net income is subject to accounting standards that allow — and sometimes require — management judgment. Depreciation schedules, inventory valuation methods, goodwill treatment, and revenue recognition timing all affect EPS without affecting the physical reality of the business. A company can report higher earnings by extending asset useful lives, capitalizing costs that competitors expense, or recognizing revenue earlier. None of these moves change how much cash the business actually generates.
Free cash flow circumvents most of this. Cash is cash. When $100 million moves from a customer's account to the company's bank account, that's real. When it moves back out to pay suppliers, build a factory, or fund working capital growth, that's also real. The accounting fog clears.
This is why a company can consistently report positive earnings while simultaneously burning through cash — and why the cash flow statement tells you the story that the income statement hides. Before investing in any business, compare its net income to its free cash flow over the past five to ten years. If FCF has consistently lagged earnings, dig into why.
FCF yield: the investor's version of the earnings yield
Once you have FCF, the valuation metric that matters most is FCF yield:
FCF Yield = Free Cash Flow per Share / Stock Price
(Or equivalently: FCF / Market Cap)
This is simply the inverse of the P/FCF multiple, expressed as a percentage. A stock with a P/FCF of 20 has an FCF yield of 5%. A stock with a P/FCF of 10 has an FCF yield of 10%.
Why express it this way? Because it becomes directly comparable to the yields on other assets. A stock with a 3% FCF yield is competing with a risk-free bond offering 4.5% — and losing. A stock with an 8% FCF yield, growing at 15% per year, is offering something quite different.
FCF yield is also how you identify the businesses that are genuinely cheap on a cash basis, not just cheap on a reported-earnings basis. The screener lets you filter by FCF yield directly — useful for finding businesses that generate substantial cash relative to their price.
FCF per share: the compounding engine
FCF per share — free cash flow divided by diluted share count — is the number most analogous to EPS for fundamental investors. Watch it trend over time.
A business that generates growing FCF per share year after year is compounding value. If management returns that cash to shareholders through buybacks (rather than issuing new shares), FCF per share can grow even faster than total FCF, because you're dividing by a shrinking share count. This is precisely the dynamic Buffett has referenced repeatedly when discussing Berkshire's approach to capital allocation: businesses that generate high FCF and reinvest it at high returns — or return it to shareholders — are wealth-creation machines.
The inverse is also true. A business where total FCF is growing but share count is expanding even faster is producing FCF per share that's flat or declining. The business looks good at the aggregate level; the individual investor is being diluted.
On the stock one-pager, FCF per share is shown alongside EPS in the per-share section — you can immediately see whether the two are converging or diverging over time.
What negative FCF means
Not all negative FCF is bad. It is, however, worth understanding carefully.
Growth investment: A company aggressively expanding into a large opportunity might run negative FCF for years because it's reinvesting every dollar of operating cash flow — and more — into growth capex. Amazon's early years are the canonical example. The logic holds if the returns on that investment will eventually be high. The key question is whether management has demonstrated it can allocate capital well.
Structural cash burn: A business that generates operating cash flow but consistently spends more on maintenance capex than it takes in isn't really a viable going concern — it's slowly liquidating its asset base. This often shows up in capital-intensive industries (airlines, commodity producers, telecom infrastructure) where keeping the business operational requires perpetual heavy reinvestment.
Cyclical trough: Capital-intensive businesses sometimes run negative FCF at the bottom of a cycle because revenue falls faster than capex can be cut. A steel mill doesn't immediately stop maintaining blast furnaces when steel prices collapse. The FCF trough reflects the cycle, not permanent deterioration.
The difference matters enormously for valuation. Temporary negative FCF during a period of high-return investment is a feature. Structural negative FCF is a fatal flaw.
Capex-light vs. capex-heavy businesses
This distinction is one of the most important in fundamental investing, and free cash flow makes it visible.
A capex-light business — consumer brands, software companies, financial services, professional services — requires little physical investment to maintain and grow. The gap between operating cash flow and FCF is small, meaning almost all of the cash the business generates is truly "free." High-quality, capital-light businesses earning high ROIC are disproportionately valuable precisely because they don't need to retain much capital to sustain their earnings power.
A capex-heavy business — airlines, railroads, semiconductor fabs, refineries — must constantly pour cash back into the machine just to stay in business. The reported earnings may look attractive, but a large portion of those earnings are required for reinvestment, not available to owners. Depreciation accounting partially captures this, but often understates the true economic reinvestment burden.
This is why comparing P/E ratios across industries without also comparing FCF conversion rates is misleading. A consumer brand at 25x earnings may have better FCF economics than an airline at 10x earnings.
How to use FCF in practice
When you're evaluating any business, run through these checks:
Does FCF track earnings? If a company consistently reports $3 of EPS but only generates $1.50 of FCF per share, the earnings are of questionable quality. Investigate why.
What's the FCF yield? Compare it to prevailing interest rates and to the company's own historical FCF yield. A business trading at the low end of its historical FCF yield range is priced for optimism. One at the high end may be genuinely cheap.
Is FCF per share growing? And is the share count flat or declining? Growing FCF per share with a declining share count is a powerful combination.
Is the capex mix maintenance or growth? Management often discloses this in the MD&A or earnings calls. If you can identify what portion of capex is discretionary (growth) vs. required (maintenance), you have a better estimate of normalized FCF.
For negative FCF businesses: is there a credible path to positive FCF? What's the capital intensity of the business model once it reaches scale? Has management explained the investment thesis clearly?
Every stock page on The Ledger Terminal shows free cash flow alongside net income in the financial table — fifteen years of both, so you can see the relationship over time. Microsoft is a useful example of the capex-light compounder: consistently high FCF conversion, growing FCF per share, and FCF yield that signals whether the stock is priced for optimism or pessimism.
Earnings are what the accountants report. Free cash flow is what the business actually earns. In the long run, they're what you own.