Free Cash Flow (FCF) | Investing Glossary

What it is

Free cash flow is the cash that flows into a business and stays there — after it has paid its bills, its taxes, and the capital expenditure required to keep the operation running. It's the number that a private equity buyer looks at first, because it represents what the business is actually worth to its owner.

The City's favourite abbreviation is FCF. When an analyst says "the stock is trading at 12x FCF", they're dividing the market value by the annual free cash flow — essentially asking how many years of cash generation you're buying.

How to calculate it

**Free Cash Flow = Operating Cash Flow − Capital Expenditure**

Both numbers come from the cash flow statement — the most underread section of any annual report. Operating cash flow is cash generated from the core business activity. Capital expenditure (CapEx) is cash spent on maintaining or expanding physical assets: factories, equipment, vehicles, data centres.

Some analysts subtract only maintenance CapEx (what's needed just to keep the business running), leaving in growth CapEx as optional investment. This gives a "maintenance FCF" figure that shows the true underlying earning power stripped of expansion spending.

Why it matters more than earnings

Reported earnings (EPS, profit) are an accounting construct. They can be shaped by depreciation policies, goodwill write-downs, exceptional items, and other legitimate but discretionary choices. Free cash flow is harder to manipulate — cash either arrived in the bank account or it didn't.

This is why a company can report rising profits while simultaneously deteriorating financially. If working capital is expanding (debtors growing, inventory building), if CapEx is being deferred, or if acquisitions are masking operational weakness, earnings will look fine while free cash flow signals the problem.

The divergence test: Compare cumulative net income over five years to cumulative free cash flow over the same period. In a healthy business, they should broadly track. A large and persistent gap — profits consistently exceeding cash flows — is a red flag worth investigating.

The capital-intensity trap

Not all businesses are created equal when it comes to free cash flow. A software company with no physical assets turns almost every pound of revenue into free cash. A steel manufacturer with blast furnaces needs to continually reinvest just to stay competitive.

This is why Warren Buffett has described capital-intensive businesses as "voracious consumers of capital." A company that earns 10% on its capital but needs to reinvest everything back in just to maintain that return is not compounding value — it's running on a treadmill.

High FCF businesses — consumer brands, software platforms, asset-light services — can return capital to shareholders through dividends and buybacks year after year. That's the compounding machine investors are really looking for.

Interpreting the FCF yield

Divide the annual free cash flow by the market capitalisation and you get the FCF yield — the cash-based equivalent of an earnings yield.

A stock with a 7% FCF yield is generating 7p of free cash for every £1 of market value. Compare that to a ten-year UK gilt yielding 4.2% and you have a rough sense of whether the equity is compensating for its additional risk.

FCF yield above 6% on a well-capitalised business with a growing cash flow trajectory is typically where long-term value investors start to pay attention.

**Watch out for:** Negative FCF isn't always bad. Fast-growing businesses often invest aggressively, generating negative FCF for years before the cash generation inflects. Amazon was FCF-negative for its first decade. The question is whether the investment will generate returns that justify the temporary cash burn.

Not financial advice. Always review the full financial statements.