Finance Explained Simply
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Corporate FinanceCash flow analysis
Beginner5 min read

What is cash flow and why is it the most important financial metric?

By the FES team · Published 14 March 2026

In brief: Cash flow is the net amount of cash moving into or out of a business during a period. Unlike accounting profit, it cannot be manipulated through estimates, accruals, or timing choices — cash either moved or it didn’t. A company can show accounting profits while running out of cash; it cannot continue operating without cash regardless of what its income statement says. This is why serious analysts often focus on free cash flow more than reported earnings.

The three sections of the cash flow statement

Operating cash flow (OCF) starts with net income and adjusts for non-cash items (adding back depreciation, amortisation) and working capital changes (if customers owe you more money, you’ve "earned" revenue but haven’t received cash). This is the most important section: it shows whether the core business generates or consumes cash. Investing cash flow shows capital expenditure on assets — factories, equipment, acquisitions. Financing cash flow shows debt raised or repaid, dividends paid, and shares issued or bought back.

Cash Flow Statement — Structure Operating Net income £50m + Depreciation £15m + WC changes −£5m OCF = £60m ✔ Core business generating cash Investing − Capex −£25m − Acquisitions −£0m + Asset sales £0m = −£25m FCF = OCF − Capex = £35m Financing − Dividends −£10m − Debt repaid −£5m + New debt £0m = −£15m Net cash change: £60−£25−£15 = £20m

Free cash flow — the gold standard metric

Free cash flow (FCF) = Operating cash flow − Capital expenditure. It represents cash the business generates that is genuinely free — available to pay down debt, pay dividends, buy back shares, or accumulate. It is the metric most closely linked to long-run share price performance because it underpins dividend sustainability and is harder to manipulate than earnings. High-quality businesses generate FCF consistently in excess of net income; lower-quality businesses often see the opposite — they report profits but consume cash.

When profit and cash diverge

Profitable businesses can run out of cash. The classic scenario is rapid growth: a business that doubles sales must also double its working capital (more inventory, more receivables) — and if the growth is faster than cash collection, the business consumes cash despite making profits. This "overtrading" has caused the collapse of many apparently successful businesses. The opposite also occurs: a business can generate strong cash flow despite reporting accounting losses (through high depreciation). Cash flow analysis cuts through these accounting complexities.

FCF yield
Free cash flow / market cap — the cash-based equivalent of the earnings yield, useful for valuation
Cash conversion
OCF / net income — a ratio above 1 suggests high earnings quality; below 1 raises questions

“More businesses die from cash starvation than from lack of profit. Profit is an opinion; cash is a fact.”

What this means for you

For any business you are evaluating — as an investor, lender, or business owner — check that it converts profit into cash. Calculate the cash conversion ratio (OCF / net income) and the FCF yield. Be particularly sceptical of fast-growing companies that show strong revenue and profit growth but consume cash: they are dependent on continued external funding. The businesses that survive recessions and generate wealth for shareholders over decades almost always have one thing in common — they generate more cash than they spend.

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